Re the last couple reblogs: the thing about all of it isn’t necessarily that having the private discord fic servers is bad. And maybe if commenting is something that makes you anxious, you want to be able to react there first and that’s a great idea.
The problem becomes if you never then share that reaction with the creator, because even if we aren’t writing for you/for the audiences and responses, we’re only bothering to post it where you can see it for that.
I mean I’m not going to lie: often we do in fact write for the response. Writing is work; I write very fast, and a thousand words of the very raw-est first-draft story still takes at least an hour just to do the physical writing, let alone the dreaming up, the planning, the editing, the remembering, and everything else. Sometimes the existence of the art in and of itself at the end is enough reward for that work - but bluntly sometimes it really isn’t.
But in addition, posting is also work in and of itself. It is effort; even when I had it moooore or less down to a cut-and-paste for YBEB it was several minutes for sorting it out, posting it and double-checking it per single-chapter fic (multi chapter fics, all the more so).
Fan-creators put their stuff up for free; fanwriters in particular create the equivalent of hundreds of thousands of novels a year which are then available for free to those who like them. (Other fan creators also make amazing efforts but as my thing is writing writing is the one I have equivalent-estimates for).
Some kind of response that the author can see and is made aware of - that is positive - is the only reward the author gets for going to the effort of, if not writing it, at least posting it where you can see it.
If you want that to keep happening, it’s probably a good idea to give the authors you like some kind of reward. And I really am speaking just of the fics you actually like a lot!
An easy way is just to have a lot of standard Delighted Responses that you can use - that much itself is actively worth it to share with the author, because that’s specifically the recognition/awareness that someone has loved it that counts. Others have suggested the also delightful idea that you just c/p the gushing you may or may not do in the private servers, and so on.
But frankly “this was delightful” or other simple handsfuls of words expressing happiness to read it is all you really need.
In case you were worried, it isn’t creepy or overly familiar to leave a comment on a fic when you don’t know the author. If the author doesn’t want comments, they wouldn’t have put it out on that platform, or they would have turned audience commenting permissions off. They put it there so you could read it and engage.