Romantasy books with an FMC that's an actual adult?

I love the genre so much but I'm 37 now and struggling to relate to 18/19 year olds lol. One of the reasons I liked quicksilver so much is that she was 24. I'm not looking for a geriatric heroine or anything, just maybe someone that would probably know how to do taxes if they were in the real world.

I like lots of steamy scenes but they MUST have subtance. I very rarely appreciate smut for the sake of smut (except for the Never King for some reason) I like a nice slow burn leading into some real good stuff ;)

Between books and craving suggestions! Thank you!!!

Edit: Holy DROVES of suggestions batman!!! This thread is going to hold me over for all of 2025 lol. Thanks for being so warm and welcoming even though this is apparently a commonly asked question!! I appreciate the internet hospitality <3 <3