BND
Vanguard Total Bond Market
stock NASDAQ ETF

If you are happy to get 4.7% and hold to maturity- buy a 10 year t bill. Rates are not a bad spot to buy a bond fund, there could be a little downside pricing risk with rates rising a bit, but it’s nowhere near as bad as the risks were in 2022. BND pretty much has zero return over 5 years because of it. Bond funds always refresh inventory as bonds mature and with longer duration funds, they replenish with long bonds that could be NG. Currently that risk is ok though. I personally buy individual bonds of the term i need, or short duration funds

The Boglehead answer is BND. The reality is more complicated.
Stocks drawdown for different reasons and fixed income is only a good hedge some of the time. The recent 2022 drawdown shows how when you get an inflationary shock with sharply rising rates, stocks and bonds can fall in tandem. A similar story took place in the 1970s.
The good news is that bonds tend to have a higher likelihood of being a good hedge for very serious market crashes. Think GFC, Great Depression, Dot Com bust, etc. Massive market crashes are almost always disinflationary with higher unemployment, generating an environment where bonds do really well. 2022 was a comparatively mild drawdown for stocks (but a serious drawdown for bonds).
There's really no such thing as crash insurance that defends against every kind of downturn (without directly betting against the market). There are other non-Boglehead options such as precious metals, managed futures, etc. But once again, every crash is different and you can't easily predict which hedges will defend your portfolio and which ones won't.

I have never owned BND and will never own BND.
ICPI for inflation protection and USDX for cash

Bond ETFs: BND, AGG, BSV, VCIT, others?

You have 10% of your portfolio in BND, ok. Why do you want to change that if not for market timing, then?
How is it not market timing if you keep talking about how this one fund is down in the OP?
Changing your AA when something is down is called market timing, literally. That's what market timing is.
I do time the market and I think anyone would call it successful if they looked at the numbers.

I know they have overlap, but if you DID have a million, how would you break it down? VOO, VTI, VT and BND.

BND is for older Bogleheads. The N is a stooping V with a cane. (I know this is a bit silly, but I had to try)

If means that if rates go up 1%, then BND price goes down 5.8%.
Another way of saying this is that if rates go up 1%, then in 5.8 years you will have (a) the interest rate you expected and (2) you have been recompensated for the decrease in the price of your etf.
5.8 is a big durantion in my book. It is nothing comparted to the duration of 16 of TLT which some people find attractive now, so it is a judgement that people will make individually.
The only way to make progress is to have a good answer to the question "For what purupose do you want to own bonds." Then as always in finance you have to come to some view of your own risk tolerence.

It's a relatively expensive (ER 0.63% yuck), actively managed (yuck) 70/30 target allocation mutual fund.
I think Bogleheads would recommend passively managed alternatives, but there isn't an exact equivalent at that target allocation. Alternatives include Fidelity's FFNOX (85/15), Vanguard LifeStrategy mutual funds (e.g. VSMGX at 60/40 or VASGX at 80/20), or iShares Core allocation ETFs (AOR at 60/40 or AOA at 80/20). Any of them I think have 1/4 or less the expense ratio of FASGX and are passively managed.
The ETFs would be better if holding in a taxable account due to capital gains distribution avoidance, and the Vanguard funds are probably better held at Vanguard than at Fidelity.
Or you could do 70% VT, 30% BND and login once a year to rebalance until you start taking distibutions.

There are lots of bond funds better than BND.

Can you do better than BND?
https://www.bogleheads.org/forum/viewtopic.php?t=424247

No, I don't drip. I use the dividends to rebalance. So sometimes I end up buying more BND but not always.

Yeah I have a lot to learn, and the bond duration stuff is completely foreign to me, especially as it pertains to index funds. If BND has a duration of 5.8 years, what does that mean in terms of whether to buy it or not?

BND(W) seems like the good default for a good reason. You could also put some in a target maturity bond fund (via iShares iBonds) if you want the duration risk to decline over time.

There are many more considerations than one might think at first. The big one is that bonds can lose money. If interest rates go up, then the price of the bonds in your porfolio goes DOWN.
Then you need to put your bonds into your tax sheltered accounts. You need to find a bond duration (reading assigment) that you are comfortable with. You have to sort out the choice of corporate or government bonds --- not easy, read what David Swensen said about corporate bonds.
Can you do BND and chill ? It has a duration of 5.8 which is too risky for my bond portfolio --- my bonds are there to provide funds when things are bad. I hold VTIP short term Tips, and VGSH short term government securities in about equal porportion. I also have ladders of some additional TIPs and some directly held US treasuries bought at auction.
There is stuff to learn and it pays ... dividends.

There's no V in BND...

As I'm nearing retirement time, and trying to understand the "bond" side of the portfolio I think about this a lot.
The "own the market" side of stocks is so elegant and perfect for me. The bond side isn't that simple at all, with so many different options. BND is a solid piece of the puzzle, but there are a lot of other things to consider (TIPS, ladder vs fund), matching bond durations to when you need the money, muni vs Treasury vs corporate, etc .. I wish there was as clear of a "known good" answer as "VT and chill" for bonds.
All of the above is general portfolio balance planning, not trying to predict any specific cycle. Bonds can have solid returns, even if they haven't for awhile.

Just buy some BND keep it simple

I like BND. Vanguard Total Bond Market Index Fund ETF

I'm no expert, but the two main characteristics of bond funds are their duration and type of bond. So, you've got ultra-short, short, intermediate, etc. and then you've got Treasuries, TIPS, Corporate, Municipal, etc.
VTIP (Vanguard Short-Term Inflation-Protected Securities ETF) is similar in duration to VGSH (Vanguard Short-Term Treasury ETF) but holds TIPS instead of standard Treasuries. VTP (Vanguard Total Inflation-Protected Securities ETF) sort of corresponds VGIT (Vanguard Intermediate-Term Treasury ETF) in the same way, but is actually closer to VTG (Vanguard Total Treasury ETF).
Investing in TIPS instead of Treasuries is a bet that inflation in the future will be higher than the market currently expects (not just higher than now). If you own TIPS and inflation continues above expectations, you'll get a better return than with Treasuries. But if inflation turns lower than expectations, TIPS will return less than Treasuries.
Generally speaking, you want to match the duration of the underlying bonds to your investment horizon.
VBIL (Vanguard 0-3 Month Treasury Bill ETF), Duration: 0.1 years
VGUS (Vanguard Ultra-Short Treasury ETF), Duration: 0.4 years
VGSH (Vanguard Short-Term Treasury ETF), Duration: 1.9 years
VGIT (Vanguard Intermediate-Term Treasury ETF), Duration: 4.9 years
VTG (Vanguard Total Treasury ETF), Duration: 5.6 years
VTIP (Vanguard Short-Term Inflation-Protected Securities ETF), Duration: 2.5 years
VTP (Vanguard Total Inflation-Protected Securities ETF), Duration: 6.3 years
For reference, here is BND and some alternatives.
VUSB (Vanguard Ultra-Short Bond ETF), Duration: 0.9 years
BSV (Vanguard Short-Term Bond ETF), Duration: 2.6 years
BND (Vanguard Total Bond Market ETF), Duration: 5.7 years