Acrylics dry, and they do dry vs curing, they do this quickly compared to enamel cure rate. So if you use a clear intercoat of clear acrylic over enamel or a second color is acrylic over enamel base color, be sure the enamel is well cured and avoid cracks and checking marking or wrinkles.
Acrylic will go over most other paints fine and most other paints go over acrylic fine with proper dry times.
Acrylic directly sprayed on plastic is asking for peeling and chipping, so use a decent primer and avoid that mess.
Some of the new acrylics are really a hybrid acrylic lacquer like Tamiya acrylics have been. Some of the new lacquers aren't so different from them. These types of paints are easy handling, thinning and cleaning up after.