Would it be best to pay off all my debts to increase my credit score

Basically I messed up my credit at like 18 it’s sitting just at 600 I have two closed accounts that I’ve been paying off monthly if I just pay them in full and close the account will that work out better and boost my score or should I just keep up the monthly payments.

The debt isn’t that high it’s about 6k (not all closed but total and the only card I have opened now is an Amex credit card if that effects anything