If you want a fun read with queer characters, Perfect On Paper by Sophie Gonzales. Also special mention to Kate In Waiting by Becky Albertalli, queer side characters and overall fun book! Can get a little sad? Maybe? I don't know but it was good!
If you want something sci-fi with a sort of alien vibe... you could try The Rains by Gregg Hurwitz
If you want something android kind of based, you *could* try The Reboot by Amy Tintera (though I used to love the book, the writing lowkey isn't my thing. But it could be a fun read? The idea is good)
Not sure where this would fall... because I suck at genres! but The Erasure Initiative by Lili Wilkinson was one of my favourites for a little!
A Semi-definitive List Of Worst Nightmares by Krystal Sutherland made me SOB! but I loved it so so much and it made me want to face my fears & phobias and get over them.
a plot-twist I never saw coming and book I overall enjoyed was The Woman In The Window by A. J. Finn! there is a movie to it also, and I *think* a series based on it? haven't seen the series though.
Sick Bay by Nova Weetman was sweet, and is likely aimed towards 14-16yr olds? I don't know the reading level it falls into but the writing isn't anything big and breathtaking, but I enjoyed it! The Edge of Thirteen by Nova Weetman is also another one to throw in!
and if you're into crime/thriller kind of books, maybe try out Gemma Rogers! I liked her book Stalker.
How to Fall in Love by Cecelia Ahern is a romance but also tackles mental health issues, and honestly one of my favourites too!
*And* a random read you might enjoy or might not, The Photographer by Mary Dixie Carter. it's a thriller and an alright read!
And before I shut up, I'd also like to mention the author Astrid Scholte. Loved loved loveddd Four Dead Queens, and The Vanishing Deep!