There have been some good suggestions thus far, but I will give you my two cents. I’ve done a lot of painting (guitars, joysticks, computers cars etc…) I would lightly sand the surface down again, you don’t need to remove all the paint, just make it a nice level surface. Wipe it down with some thinner, and repaint it. once the paint is completely dry, apply 3-5 coats of a water based polyurethane. Don’t bother with clear coats, especially the stuff that comes out of a can. They just aren’t durable enough to stand the test of time. It might work fine for some projects, but joysticks take a lot of abuse. As far as the water based poly is concerned, it is probably easier to use a wipe on product, or even one that can be painted on with a foam brush. They even make VERY fine bristle brushes specifically for water based poly, and it won’t leave brush marks. You can take it a step further and wet sand then buff it to perfection. Either way, Poly is the way to go. It looks great, and is very durable. Especially in comparison to clears out of a can. If you have elaborate spray equipment, then you could mix a 2 part clear, similar to whats used in automotive finishes, but I’m assuming that isn’t a possibility so I’ll leave you with that. Hope this helps.