Did 25 levels of quickplay and you will not learn anything in term of team play anyother 25 or 75 levels will not change anything, qucikplay will be same as bad and you will not learn. You will learn much more faster in competitive. If you are not good enough you will drop in SR. Only issue I have is initial placement, where people are played way too high.
Only things new players would learn in QP with more levels would be bad habits.