Maybe duplicate the file, then convert it to a new file type and try to run it? I'm sorry, I've never used unity but this might work if HTML 5 is the problem, it could just need to be a different programming language.
ive exported a game into html 5 before its just this one project isnt working. if it helps other things wernt working either like sound.
I don't mean export it into HTML 5, I mean maybe turning into .jar or .py, or even .sb3, which may run better.
