My assumption with changes like SAB 122 is that might light a fire under bitcoin companies like Strike to offer collateralized products before banks, so you might only need to wait another 3-12mos before some decent options are available.

Otherwise I was wondering if it makes sense to just take your entire stack minus some legacy amount, and divide it by the amount of years until you're 90 or so and consider that your allowance every year.

Maybe just talk to someone who's already been retired for some years and see what they think.