The conventional wisdom was never to use 1st person singular as your character's POV. It's wrong. There are plenty of good novel series that are limited 1st person, such as Steven Saylor's Roma Sub Rosa series. In other words, you the reader are in the head of the protagonist. You see what he or she sees, hears, and does. Above all, these do not sound like an 8th grader's creative writing project. Why? One reason that I found was to make sure you as the author don't reveal too much or give the character too much insight in the middle of the story. For those who want to write using 1st person limited POV, I do think it's doable. Read it aloud and ask a friend to be your beta reader. Let me know what you think works or doesn't.

hmmm, it's definitely doable ... when my daughter recommended 'the empyrean saga' from Rebecca Yarros some time ago, and as I know that I generally like her reading stuff, I started reading the first book, 'fourth wing' - and upon the first few sentences realized that it was not only written in the 1st person but also in the present time - so, I put the book away and told her that, 'thanks, but no thanks' ... some time later I started the book again, as she insisted that it's one of the greatest books ever, and after suffering through the first few pages, I actually got used to it and even started liking this particular kind of writingstyle - so, yes, even though I rather use 3rd person and the past while writing, if anyone wants to write in 1st person and/or present time, I'm sure it's not only a challenge, but also a good way to experiment, and a chance to create something really good ... just be open minded if you use your imagination for writing ... :) ...

I feel like convention varies based on genre. It's pretty common in romance, and by extension things like paranormal romance. I think it depends on how tightly the plot is tied to one (or max 2) characters.

Roma Sub Rosa is actually a historical mystery series. The protagonist is Gordianus, the first private detective in ancient Rome. He interacts with the great men and women in the late Republic, such as Cicero, Pompey, and of course, Caesar. A first-person POV private detective was new the first time I read Saylor's books back in the 1990s. He might be one of the first and few who writes a detective novel this way.

I used to exclusively write in 3rd, because I didn't like revealing too much of what was going on inside my character's head. I also I didn't want to inadvertently put too much of my own thoughts into my character's personality. However, I wrote a short story for an anthology. When the editor went through it, she told me it felt too detached and to switch it to 1st. It made a world of difference, so now I always test my writing out in both, just to see which fits better. I've written a lot more in 1st since, as it seems to give my writing more emotional depth than I'm able to in 3rd.