Hi and welcome to PC!
Yes I can totally identify with what you have written. I particularly have OCD tendencies when it comes to grammar (especially apostrophes!) and spend ages rewriting text and tweaking emails etc before I send them.
It really bothers me that I can't do this in therapy with speech, and I think I come across very differently in person than when I write. This adds to my existing social anxiety.
My T has encouraged me to bring my carefully edited writing to session and read it out. This way I can get used to articulating myself verbally without having to worry about being immediate and unedited. Slowly (and alongside growing trust) I have become more able to talk to him somewhat openly, and this has transferred over to real life to some extent too.
I don't know if that helps at all but it's certainly been my experience.