There was definitely a lot to glean from the responses to your post! I originally dove in because my personal definition of YA is teen angst, illogical/emotionally driven decision-making, and underdeveloped characters (e.g. The Lunar Chronicles series, most especially ‘Scarlet’).
I saw you mentioned Red Rising and was a bit surprised, since I would not classify the series as YA. After Red Rising (already barely on the edge of YA), it rapidly becomes much grittier and has none of the tropes I attribute to YA books. It’s based on rebellion/uprising, revolution, war, and coups. I hope you take a chance on the rest of the series, as it only gets better!
Personally, I’m dragging my feet on starting book 6 (Lightbringer) because of how violent and (oftentimes) depressing it gets. And I don’t mean that it’s gratuitous violence, just that it’s very in-line with the reality of that universe and the situation the characters are all in. I’ve never avoided a YA book for those reasons; only avoided YA for poor writing and dull characters 😆 the audio books for the whole Red Rising series are absolutely the way to go! Hope you continue to enjoy the series.
ACOTAR was definitely a slog for me. The prose was quite bad imo (how many times can a person “bark” something, seriously, stop) and the main character seemed fairly one-dimensional. The second book is better and the third book was… OK. I really loved A Court of Silver Flames (book 4?) but that’s because it follows her sister Nesta instead, who overall becomes a much more interesting character through the series.
There are definitely great YA books out there, but lots of duds, too. As you said, nebulous!