It depends on what you mean by being financially set. Bitcoin could hit 150,000$+ in 2023 which means if btc comes down to 1500, it could go x100 in the next boom. If being a millionaire is what you classify as being financially set, then I suppose 30 bitcoins would do it. But remember, diversification is key. Let's say I have 45,000$ to invest for the next boom. I'd divide that money into 4. With these, I would hold not only btc, but also 3 other coins that could go x1000+ (let's face it, a couple of them would) after the next boom. All four might not be successful up to my expectations, but I would make way more money than I ordinarily would if I had accumulated bitcoin only.
I would definitely not just buy 3 altcoins with 75% of my money. Bitcoin is the one sure thing. If you pick some altcoin it could 1000x (very unlikely), 100x (unlikely), 10x, 1x, 1/10x, etc. Any altcoin is a risk, some will disappear by the next crypto boom, and you never know how high others will go so you might sell way too early or way too late. We know Bitcoin will have a massive boom and I think its a lot easier to predict a general range for the next peak (though of course could be well off still). With bitcoin I'm thinking the next peak will be $100k-$150k. Personally I'm gonna sell most of my bitcoin probably just under $100k just in case it fails to break it, and will keep some to sell over $100k cuz i think it probably will break it. But there is no way I could remotely guess what any altcoin will peak at on the next crypto boom, I could easily sell an altcoin at 20x and then it goes to 80x, or think its going to 80x and it only 10x's.
So for me I'll be putting probably 90% of my crypto money in bitcoin, and put a small allotment into maybe a dozen or so altcoins just for a little bit of diversification.
Anyway, my question wasn't in general how much would it take to be financially set, which is how a lot of people seemed to take it. It was a personal question, meant to have a different answer for each person because everybody has a different idea of what the price will be at on the next boom and what they need to be financially set. I think at 25 Bitcoin I'd be set for life if I average selling say just under $100k per bitcoin. Diversify that into stocks, and keep some to buy back a few more bitcoin on the next bottom in a few years, planning to simply spend that bitcoin in the years/decades to come as spending becomes easier with adoption gains.