Dunno about you guys but there's no bigger turnoff for me when it comes to fanfics (or any fiction in general really) than it being written in first person without any framing device to justify it
like... for example, fanfics for "The Magnus Archives" have alot of first person pov fics but it's specifically bc they're usually "statement fics" aka. written like they're transcripts of an episode of the podcast, which mainly consist of ppl giving statements of something supernatural that happened to them or someone being compelled into giving a monologue.
original fiction examples I have are stuff like "Perks of Being A Wallflower" which is written like they're letters to someone, or "Diary of a Wimpy Kid" bc.. well, it's a diary.
these makes sense to me and so I can read that an enjoy them, but if the fic is just a plain ol first person pov with nothing explaining why I'm suddenly reading someone narrating things happening in their own life in eloquent prose, it just kills all my motivation to read it.
Especially when in present tense, bc it feels the least sensical for that reason but past tense still feels weird bc while it gives me a chance to make up my own framing device that's still me doing more work than I should to enjoy reading something.
I think the only way I could ever rly enjoy reading a 1st person POV fic in present tense and no framing device is if it was written as a stream of consciousness. Bc again that makes the most sense to me.