tip: katekyou "alternate universe" sort:>words
That is honestly too bad your anxiety is preventing from interacting with the other writers of the fandom(s) you're involved in. Have you ever tried making drafts of various kind of comments (ie. "I liked your story", "I liked your story, especially the part where [x] happened", "I really liked the way you wrote [x]") and then just... fill in the blank and copy/paste to comment? Maybe doing it on Anon could also help you? Baby steps?