Im stuck in a dilemma, how do you choose how much to allocate on single stocks?

Most say ETF 80:20 Single stocks split.

But if you are strongly convicted in a stock, that just feels like diluting the gains, when you could have just gone all out one the single stocks.

But then again you could end up like intel stock guy.

But then again you could end up like nvidia stock guy.

How do you solve this dilemma? i mean it is a gamble at the end of the day, regardless of how strongly you feel about a stock, but at same time, taking this gamble feels worth it because if it does work it means you just fast-forwarded a few years and got bigger rewards, but then i guess if it fails you''ve gone backwards in time a few years but honestly this is a lot of buts in decision making.

Or you could just not get the greed best of you and just accumulate wealth in index funds.

in short, seeing people just buy some blue chip stocks and end up with massive returns has made me jealous and question my own etf strategy, like why am i wasting time when i could have just bought 1-3 blue chip stocks