Psychotherapy (esp. CBT - cognitive behavioral therapy - and ACT - acceptance commitment therapy) has been very helpful to me to understand how this works. The fun part has been observing how a professional operates and the effects it can have on someone. So I jumped right into psychology studies. It’s fascinating. It helped me understand my behavior further.
There are good introductory books such as « Happiness Trap » (this one is about ACT)
Then lots of reading and experimenting. Related thread (and great article from a fellow perfectionist) « Unlearning Perfectionism » https://news.ycombinator.com/item?id=30223559