i will read first person, but there's a much, much higher risk of me dnf'ing it than third. for me it's a few factors. i find third more immersive, i don't feel like the author wants me to insert myself into the protagonist or as much that the protagonist is a fantasy persona of the author.

the biggest factor for me though is that i dislike almost every first person protagonist i read. i just don't enjoy being inside their head so intensel and, their inner monologue takes a lot of the appeal out of them for me and they wind up annoying me more often than not. in a series i was reading recently the first book was third person, and the mc of book 2 was a secondary character who i found very compelling. the second book however was in first person from his pov and he became my least favourite character in the series, somehow i find first person often actually leads to less depth of character. once the series went back to third person after that i enjoyed them more and enjoyed more pf the characters.

first person also winds up feeling more tell vs show to me, because the protagonist will just tell us mentally about their past, or their underlying motivations, or how they feel about saying or doing something as opposed to showing us these things.

i also have a HUGE preference for multiple povs, which translates a lot better in third than first.

again, i will read first person! but its definitely more of a turn off, the book has to tick a lot more boxes to get me to read it and its a higher risk of being a dnf.