It is not clear if your team is under-performing or actually performing at its level. - While you did not share your own technical background, you say every te

It is not clear if your team is under-performing or actually performing at its level. - While you did not share your own technical background, you say every team member is "capable of writing logical, working, and tested code". How did you evaluate them? - They are deemed "capable" yet you note they "deliver work that ultimately fails the QA process." Are they "capable" but refusing to write tests? Are they writing "tested code" that is actually broken? Or does the individual worker product "tests" OK in isolation but fails at the integration level? Without meaning any offense, I think team (technical) leadership is the issue here. You may get more actionable feedback if you share how you are managing this team and what you are bringing to the table. There are only 4 of you. It may also be necessary to have a clear incentive structure for your team. IFF team leadership is not the issue, and there are no consequences to a continued pattern of "under performance", you can expect more of the same.