I actually sanded mine and repainted it. It was white and I gave it a colorful makeover. There are spray paints just for plastic. The key for me was several very light coats. I know that takes longer but you don't have a problem with drips.
Painting is always a great fix. There are so many different colors available now for plastic. I agree to sand it first. It does help it adhere better. Good luck!
I just updated my daughter's plastic playhouse using spray paint. I used Rustoleum brand spray paint (just my personal preference). I cleaned and dried well, used a plastic spray primer first, then sprayed with a color that also had primer mixed in. Be sure to let your project cure well in-between coats for optimal bonding. You can read my full DIY details here if you'd like more info. : ) https://themartinnest.com/plastic-playhouse-makeover/