that kind of thinking could result in repeating your mistakes.
It's about _past_ decisions, nobody says you shouldn't care about doing the best for you in the present. You can't be sure if your decisions are the best, but you surely have to avoid the bad one if you can !
The meta level is to recognize classes of mistakes and create a process around preventing them to help avoid future mistakes.
i dont really see how you can say free will is an illusion so you shouldnt do something.
Thats a direct contradiction
No, if free will is an illision, then even "choosing" to believe in it and "choosing" to let things go is an illusion. It would apply to every "choice" we make.