I have limited experience with this, and I am by no means a professional, so take this fwiw….
I redid a guitar several years back, and the method we used was to sand it after every coat, and use very high grain sand paper, and wet sanding. Eventually we used a high gloss coat and buffed it.
Recently I made an arcade machine and attempted a high gloss paint that wasn’t supposed to need to be sanded, so I didn’t sand it. It definitely still came out glossy, but there were small “bumps” and lumps in it that upset me and would’ve needed to be sanded out… but unfortunately would’ve given me different shades throughout.
Pending what you’re painting I would almost just tell you to get a professional to do it, lol.