The most serious novels you've ever read

Hi! I'm looking for mm romance books (or plot-driven books with gay romance in them) that have a serious feel about them. I love the romcom vibes once in a while but I'm looking for something that will... Hell, how do I even explain it... Every story can be turned into a cometic relief. I guess I'm currently looking for something opposite of that. Not necessarily filled with angst, just feeling really visceral and grounded in reality.

Eg if the setting is post apocalypse, I would like to really feel the gravity of the characters' situation and the struggles they endure due to that setting. So that the small moments of joy and laughter are even more precious.

Or if the story revolves around eg two military men attracted to one another who work together, I'd like to really feel that sexual tension. But not as something that is just fun and makes them feel shy or naughty. I rather it's something that can be as exciting as it can be inconvenient and frustrating. Or even scary and dangerous to feel it in their line of work and in the toxic masculinity environment they're often in.

I want the setting to feel tangible and the stakes to feel real.

Please, feel free to just share your recs with me but I'll also really appreciate if you tell me what you enjoyed or hated about the book you mention!

EDIT: Thank you for the recs so far and I want to say that genre doesn't matter - contemporary, fantasy, horror, sci-fi, anything works for me!

EDIT: BIG THANK YOU FOR ALL THE RECS!