I worry the same way, but mostly just when I'm commenting on something hurtful. Like if a commenter is being agonizingly wrong about something really important, spreading lies, you know the kind. I'll get worked up and start writing a comment, but realize that any point I make can be nitpicked and invalidated even if it's broadly correct. So I don't post those comments.
But when it's not in response to someone being inflammatory, I feel better about just doing my best with what I write. If someone has a correction, well that's a good thing! I'll acknowledge it and edit my comment to include the better info I'm given. I can hope that the people reading it don't see that I was wrong on one point and decide I'm completely wrong because I try to interact respectfully.
>edits comment for 10 minutes to make it as succinct as possible
>realizes it has nothing to do with parent comment
>deletes comment
Back on reddit, a good half of the comments I would have left got deleted as soon as I posted them. Lemmy has forced me to make sure I've said something relevant, because if I leave a comment and then delete it, everyone gets to know that I did that, and that makes me feel even worse than saying something slightly off topic