We regret about missing Bitcoin, then about XRP then about Ethereum then Doge then Shiba then Pepe (these are some top of my head and from what I've come across in my crypto term).
Point being there are always new opportunities and dwelling on regrets is futile.
The problem with humans is we always regret for what we missed despite knowing that there was a good chance that we might still not have entered it even if we had an idea about this thing. If I'll tell you today that this shitcoin could rise you'll still call me a stupid and might not agree with me but you'll surely regret it once you see it reaching new heights, fact is that your decision of not believing me was absolutely correct if factually this investment looked wrong to you, other than this you can't do anything more all you can do is trust your own fate.