Sadly it’s something of a perenial problem in my writing and one I have never yet solved. I don’t class my books as YA despite writing a lot of YA characters. But others class some of my books as YA - and I certainly do a lot of talks and workshops to teens as a YA writer.Maybe it would help to focus on who you are writing the book for, rather than what you are trying to create. Who is your target reader?
Notwithstanding YA novels tend to be written with a young protagonist, it is the target readership and the way they are written that defines them I think. So are you writing YA that happens to have an adult as one of its protagonists or an adult book that happens to have a teenager as one of its protagonists?
A change in perspective might help bring clarity to your framing issues or marketing if that's the case.
This one I would class as adult. I suspect agents and publishers will find it a problem. In which case, it’s self publishing it is for me