i have kept as much as 3 years worth at the current burn rate (that burn rate does not include traditional regular income from ETF etc) on fiat in there. plus the regular burn rate is in large part covered my my tradition stuff.. 401s, etf, stocks, so even if btc crated tomorrow i *should* bbe set.
The "standard" that is often recommended is 3 to 6 months of current burn rate. For your fiat or cash emergency fund.
Interesting that you have 3 years. Although I have read about one traditional early retiree (or maybe he isn't retired yet), that claims he has 7 years worth as his emergency fund. I think that is too much, but hey, that's his comfort and safety level, and good on him for that.
Considering the bitcoin cycles, I'd say 3 years is good, 4 years might be better, but beyond that might be wasting your money unless you have more than you really need.
I mean, if that guy loses all income for 7 years, he should be good, and still have his capital or other investments intact.