Honestly, I only like the professor so far... The others are too crazy

yeah I like the professor but it still feels weird

True, the age gape is pretty fucking big and he's supposed to be her teacher and all

I think we need to differentiate romance with a big age gap from grooming and predatory behavior... both exists and at this point things between the characters are none of them.
I'd like to remind you that the world mc is in is based on a dating-sim game she was creating. The professor is a stereotypical kind of character because there are players who are into older guys... and tbh I've seen more than once girls crushing on young teachers... boys on female teachers too.
But again... this is neither a treach being a creep nor a student having a crush. I do get op's opinion because until now he is the only one that acted like a normal person towards mc... neither too hot nor too cold... and he didn't do anything that crossed the line from what a proper teacher behavior is like...
Honestly... I don't like any of the ml's... but I like Osvald best... because he ain't a character in a game she made... and I'd like to see mc becoming a higher being instead of choosing to become part of that world and as such he'd be a better choice... but Ik this won't happen anyway....
Also... on that age note... mc is originally an adult woman... so she ending with a teenager is also weird...