Have you considered using enamel paints? One Shot or even Testors for model cars? Far more durable than acrylics. I’ve had uncleared touch ups last years on heavily played machines.
One Shot is durable enamel made for sign painting, I’ve had lettering on the side of my outdoor parked pickup truck for about a decade and the red is still vibrant so it definitely has UV inhibitors. Yes, they cost more than art store acrylics but I just buy the primary colors and mix my own custom colors so you’re only really buying a few pints.

I have at least one or two thousand plays on one particular game touched up with Testors enamel (and kept clean and waxed.) It still looks great.