I struggle with this, too -- for decades! I am glad you started this thread so I could get some reminders about what other people do.

Sometimes, I write out what is going around in my head. It helps to get the dirty laundry on paper, for me. It seems to get the self-criticism out an endless spin cycle. Sometimes, I have to do this everyday and, when its especially bad, I am writing fool frequently during the day.

If I have an upsetting bout with a student, and I think I've done it all wrong, I even take time out from the workday to write out what happened, what I should own, what isn't my fault, and what can do about the part I own. Thanks for the reminder about ownership, KimmieDawn.

Talking with others as you are doing here to get other points of view also is helpful when the bad voices are nattering at me.

There is a book called Radical Acceptance that has a whole procedure to follow to deal with challenging situations.

Thanks again for starting this thread, and best wishes for self-forgiveness.