Usually 4%/x25 has been considered the rule-of-thumb (and that’s based on a study that considered dying broke okay; not based on capital preservation). x20 would usually be considered fairly aggressive (although that depends if you are including other things like SS benefits if you are in the US).

Given the super-high CAPE ratio currently, even 4% would be be aggressive if you want capital preservation. Something like 3%/x33 would be more geared towards that.