Some people wax their pinball cabinets with modern carnauba wax and use buffers.
It works if used with touchups with ENAMEL paint.
A lot simpler than using automotive clears, and does give good protection including decaled, stenciled, and screened cabinets.
Many urethanes YELLOW with age, and certain clear coats will STINK for months.
I have done this for years, and keeps cabinets looking good.