The theoretical maximum per flip is doubling your money (if you had a way to just bet on fair coin flips)
You shouldn’t settle for 4%. You should be able to get to at least within 10% of optimal, certainly at low bet sizes.
Find an asset that is likely to either double or go to 0. For small amounts you can just pick sports games, learn which side will win then bet on kalshi or polymarket which won’t ban for winning every time. Plenty of 50c priced assets. That gets you to 7 figure size
Then you go to option spreads that expire soon at the money, although if you need to source a new bet every two hours that can take 7 figures in liquidity it gets complicated quickly. Probably best to only use it for doubling money once a day, and use the other flips for more helpful research. Once a day you can do something like “if I buy a 0dte call spread on SPY around the current price, it will end up profitable” and sell the call spread if not, if you do a narrow spread then it almost always ends up outside the bounds. You can roughly double 5 times a week this way, which should be enough for anyone.
Can we stop saying that FDT says you should never give in to threats? The theory only actually says that when you’re dealing with sufficiently good simulators whose behavior depends on their simulation of you. That almost never applies.
Separately, the fictional version of decision theory from dath ilan found in planecrash says to never give in to threats. That is not FDT and is not fully explained.