SEPP
PGIM S&P 500 Buffer 12 ETF - September
stock BATS ETF

Almost no custodians determine exceptions any more. It’s pretty much always ‘1’ for a traditional IRA or ‘J’ for a Roth, and it is up to you to justify it to the IRS. I just finished a SEPP with Fidelity last year, and even though it was registered with them as SEPP and I was getting those regular payments per the SEPP, I still got code 1. You just mark on Form 5329 that you qualify for an exception, and give a reason code (in my case, the reason was ‘02’ for SEPP).

if you have a huge tax bomb coming then you will have the flexibility to retire early and do roth conversions, pull down with SEPP, or simply start drawing at 59.5.
No harm in considering future implications and no doubt roth dollars give a lot of flexibility. I wouldn’t overlook 401k just because of the RMD.

Almost no custodians determine exceptions any more. It’s pretty much always ‘1’ for a traditional IRA or ‘J’ for a Roth, and it is up to you to justify it to the IRS. I just finished a SEPP with Fidelity last year, and even though it was registered with them as SEPP and I was getting those regular payments per the SEPP, I still got code 1. You just mark on Form 5329 that you qualify for an exception, and give a reason code (in my case, the reason was ‘02’ for SEPP).

if you have a huge tax bomb coming then you will have the flexibility to retire early and do roth conversions, pull down with SEPP, or simply start drawing at 59.5.
No harm in considering future implications and no doubt roth dollars give a lot of flexibility. I wouldn’t overlook 401k just because of the RMD.

Separate from the ETF advice, if you're actually planning to stop working, look into Rule 72(t), often called SEPP, regarding how to withdraw from your 401k without penalties before 59.5. If you only have $500K liquid and the rest is in your home equity and retirement accounts, I think you'll probably need to go this route.
As for whether or not you should focus on dividends or just selling, I think just selling is appropriate for most people, so long as you understand how to mitigate sequence of returns risk (either a cash buffer so you don't have to sell when your assets are down or the ability to greatly lower your expenses, so you don't have to sell as much).
As for which funds, it's going to depend on your risk profile and how adverse you are to your principal dropping. I would probably consider one of the following: VT, AOA, AOR, or AOM. All are globally diversified portfolios, the difference is how much is allocated to bonds. VT is 0%, AOA is 20%, AOR is 40%, and AOM is 60%. This results in VT being the most volatile and subject to the largest drawdowns while AOM is the least volatile and subject to smaller drawdowns. Though, on the flip side of that, VT is expected to have the highest long-term returns while AOM would have the lowest. So the choice is largely about balancing long-term growth against short-term volatility.