FWIW, that's essentially just gap-filling with more steps and increased procedural risk; the varnish (polyurethane) is already a component of the spray paint, and the steps as described leave an incredible amount of room for failure on multiple points. It's reinventing the wheel and boxing it up as a lifehack. 🤌🏼🫣
Uh... That's where you're drawing the line? That very specific, all but arbitrary point along a path already littered with ethical failures? Really? 😅 I mean, you do you. 🙇🏼♂️🥲
One of these days, your perspective might change a little, heh —but try not to get dragged down by the myriad crimes against humanity inherent in plastics, et al industries... 🤷🏼♂️
Change what you can, working from yourself outward. Use PPE, sand your plastic gadgets, do a good job, bring joy into the world with your efforts. ✊🏼🫶🏼
Frankly, a few dozen passes with 120-220 grit, (with the grain) followed by a quick acetone wipe down (picks up any particulate) and then a couple light coats of gloss varnish (spray; 8-10" away, just enough to begin saturating the surface) varnish before waiting 24hrs+ (ie. gas off) to box it up... is the pro move here. 🫶🏼🤓
Ah, you have chosen the path of pain.