I have fiberglass enclosers reglazed all the time. They look good when the job is completed. The tubs I have reglazed are in rental units, and usually the tenants will use an abrasive cleaner and the tub will look scratched and dull again in as little as 2 years. I suppose if it is for your own use and the encloser is structuraly sound reglazing could be an option. The key to long life is using a non abrasive cleaner, and absolutely don’t use a bath mat with the suction cups on the bottom. There are numerous companies that do this type of work depending on where you live.
Hello, You can try buffing out the tub/shower with the same type of buffing compound that you’d use on a car and use it the same way. Although if it’s beyond saving (scratches too deep) then you will need someone to refinish it. Good Luck!!