You won't have to regret if you sell your coins still at a reasonable price, as long as you're not losing, then its something you still have to be thankful. However, if you regret of not buying ETH when it was very affordable, and prefer to hold shitcoins and meme coins, that is definitely a valid reason to regret. Apparently, you are not holding them to make profits, but to lose your money, time and effort. For me, i do have my own regret and that is not buying bitcoin when its still very cheap. So i make sure i'm not doing the same mistake again that i may regret in the future.
This is basically how I try to approach things. I made a good profit by selling my bitcoins back in the day, and it was actually quite good, like made 15x return and that was awesome, how would I know that it would have gone up even more
.
So, yeah I could have been very rich, literally like buy a whole apartment type of super rich person and that would have changed my life, instead I am living comfortably, do not have too big of a debt, nothing that I can't pay up today, and still working to survive, if I lose my job then I will lose all my income and I would be suddenly poor. That is the difference between "making profit" and "keep holding".