SGOV
iShares 0-3 Month Treasury Bond ETF
stock NYSE ETF

I dont think you know what safe is. Its an agressive portfolio you listed of funds that use derivatives and some leverage.
Bitcoin has dropped 80% before. Which if that happened when they go to sell calls against it, you are now limited on the upside and the the fund has less assets to sell against reducing yield.
Your portfolio would be down significantly in a 2008 or 2020 covid drop. The only safe fund you listed is SGOV. Your portfolio has significant systemic risk.

SGOV or VBIl. if you want a little more yield, XHLF. I wouldn't go beyond 6 months.

Market timing is a tough game.
That said, park your money in a short term bound fund like SGOV, etc. and if you live in a state with income tax, you avoid it with these funds over a money market.
Anything else is speculation and you may be wrong. People were shocked during the GFC when their corporates tanked.

I put some of my sgov into BOXX recently. I intend to use the funds to pay my mortgage, for which the entire balance is sitting in treasuries in a cash management account. I certainly like the idea of capital gains treatment, but the spread is a little less because I expect to pay state tax on the BOXX LTCG, which is waived for SGOV

Depends on your goals. What are your goals with your finances at this point in life?
Something to bear in mind with bond ETFs is that *you can lose money on them.* Like you're not quite guaranteed a "hold to maturity and get your principal back" situation, and long-duration bonds can come with appreciable variability due to interest rates.
Short-duration bond ETFs, like SGOV, are very safe from downside protection, but yield can quickly dry up when interest rates fall.
Again, the #1 thing is to clearly identify your goals and needs. But something to consider, if you're looking for preserving your funds while earning some interest, would be a bond or CD ladder. You own the bonds directly, collect interest either on a regular basis or at maturity, and you get the full principal back at the end (assuming the lender doesn't default).

I'm very sorry for your loss. My advice would be to put the $250K in a safe/cash-equivalent type of investment, such as a good money-market fund, or an ETF like SGOV or VBIL. The latter two invest in very short term treasury bills, so it doesn't get much safer than that. Since you said most of your stuff is at Vanguard, you could put the funds in VMFXX, VUSXX, or VBIL which are all Vanguard funds. This can all be done within an existing brokerage account, or you could open a new one.
This approach, for now, keeps the money safe while you work through the grief of losing your wife and continue to learn more about investing.
I recommend reading all the Boglehead material referenced here in the sub. Also, Google "JL Collins free stock series" and read all his writings. Alternatively, you could purchase JL's book. It's an EXCELLENT education on how to invest. If you like listening to podcasts, JL has been interviewed on many if you search for his name + podcast.

This is what I have: BITO; BLOX; QQQI; GPIQ; FSCO; PDI; IDVO; IGLD; BIZD; UTF; UTG; BST; SGOV.

In my opinion:
1. Emergency fund doesn't necessarily need to be in a brokerage account. Lots of other good choices too such as (for example) a savings account at a local brick-and-mortar bank.
2. For a person such as yourself with the know-how to buy t-bills, I don't see much advantage to SGOV. While it is true SGOV has a low expense ratio (only 0.09%) why pay even that, if you don't have to?

Do you need to hold SGOV through the end of the month to receive the dividend? I had to cash mine out on November 28 and didn't receive a dividend for that month; I'd been under the impression the dividend accrued regardless of when you buy and sell, but now I'm feeling like I'm an idiot, and looking for confirmation of such?

I feel the same, especially with current valuations being very close to the dot-com ratios.
Currently sitting on 15% cash / SGOV, gradually increasing it towards 25%-30%.

You can open a self directed investment account right through the chase app, and put it in something like VUSXX or SGOV if you just want a higher savings rate. You can also invest in VTI/VXUS and beat the vast majority of investors if you want to put it in stocks.

The longer you invest, the more you'll learn to tune out the noise. I had to fight the feeling of hating to lose money for so long, to learn to tune out the jitters, to stop worrying every time a stock sells down to support because of some random news item, etc. Every last investor will tell you they made a crazy amount of mistakes, and to this day still do.
I was too young to invest in 2002 though I remember it vividly, but 2008 resulted in my best investment opportunity of my life because I kept powder dry. And it wasn't in stock: it was in real estate. This doesn't even mean you have to sit in cash: USFR/SGOV are great places to just stash cash. Ignore anyone who tells you that you have to be 100% equities 24/7.

I just buy XHLF XONE and SGOV instead of actual treasury.

It still sounds like a word salad. There is some confusion about what the total net return is for these 13 stocks (let me call them all "stocks" for simplicity), so I "did the math".
The value of most of these stocks has appreciated since 2023. Some of them dramatically. A couple of them are sideways. SGOV is sideways by design - but I don't think there is a financial manager in the world who would suggest that having a small portion of your portfolio in bonds is "bleeding money". PDI is down by -6%. Nothing dramatic. Overall, the value of this basket of stocks, assuming equal weight, and not including dividends, has appreciated by about 15% since Jan 2, 2023.
Not a bad return for 3 years. Not spectacular, but not bad. Total inflation for that time period to now is roughly 8.3%. Call it 9% even though we still don't have December's numbers yet.
So on that basis alone its an inflation-beating portfolio.
Add in the dividends, and its an inflation-crushing portfolio. I still don't get why you think its "bleeding out".

If most of your money is traditional earned income, there's little you can do.
1. Max tax-advantaged accounts (t401k, backdoor rIRA, mega backdoor r401k if your employer/plan allows it, HSA if the accompanying HDHP meets your needs).
2. If you have kids, consider 529s and DC FSAs.
3. Do some basic tax loss harvesting where you can, but things like direct indexing or options-based loss generating strategies are going come with management costs, complexity when you ultimately leave those funds, or worse (if you attempt to DIY it).
4. You can eke out a bit of tax-adjusted return in your emergency fund if you choose treasuries or a similar short term fund like SGOV over a HYSA. Not nothing, but not a ton, and more relevant if you live in a high-tax state.
5. Pay attention to asset location as well as allocation (not a high-earning specific point, but relevant nonetheless). That is, if you follow a 3-fund approach, put your bonds in tax-deferred, international equity in Roth, and US equity in taxable brokerage.
6. A lot of what you otherwise hear in this area is nonsensical, doesn't pass the sniff test as far as what's kosher, or isn't worth the effort involved.
Taxes matter but shouldn't induce you into a inferior investment decision unless you've very carefully determined that the tax benefit clearly offsets the delta of a slightly suboptimal choice (pretty rare).

SGOV did around 4.4% in 2025….and it will do around 3.2% in 2026. I also hold SGOV but I’m getting ready to get rid of most of it as interest rates keep coming down.

If you want to keep it simple, leave 50% in SGOV and put 50% in VOO, then rebalance once per year. This is a legitimate long term investing strategy with great risk-adjusted returns. It's called the couch potato portfolio. Look it up.

What are the alternatives? I expect the biggest reason to utilize CLOs is for the increased risk exposure (i.e. return) over a MM or SGOV. If rates go down, I expect the distributions of MM, HYSA, and SGOV to also decrease, but CLO's will remain at an elevated risk premium.

When you have state income taxes buy treasuries or a treasury fund like SGOV through your brokerage account.
Although rates are similar to CDs, no state income tax makes the after tax yield higher. A 3 year treasury yielding 3.5% is like 3.85% fully taxable for a middle class California resident with a 9.3% income tax rate.
Treasuries are also more liquid than CDs whether at a bank or brokered.

I got over 6% with just SGOV and a municipal fund last year. Municipal funds are exempt from state and federal taxes. I live in Michigan so I bought blackrocks MIY municipal bond fund. 60%/40% MIY and SGOV, blended dividend yield was over 6% and total return over 7%. SGOV will have a lower yield this year, but I should still make around 5.8% dividend yield.