Is my perfectionism really a way to protect myself from criticism?

You have already seen the thing most people never let themselves see: your perfectionism was never really about the work. It is armour. If the work is flawless, no one can wound you through it. So you have been managing your own tenderness by making the output bulletproof. That is a heavy way to live, and an exhausting one. The trouble is that the armour does not actually keep you safe. It just moves the fear inside, where it runs your days. And it does not work anyway, because perfect work still gets criticised, and you still feel it. You cannot build a version of yourself so polished that no one can ever find fault. Trying to is a full-time job that never ends. So let a little of the criticism reach you on purpose, in small doses, and notice you survive it. Share something before it is bulletproof and let someone respond honestly. The goal is not thicker armour. It is learning that you can be found imperfect and be fine anyway. That is where the real safety is, and it was never in the work.