GEL Coat options on new to us camper

Solar - google up "gelcoat buffing" (or polishing) Lots of articles out there. Most gel coat products come in a 'line' in order of use, ranging from final finish protective waxes to coarse rubbing compounds. How coarse a product you need is determined by your own coating - start finer first, than use coarser if needed. Your gel coat is probably about a mm thick - this can be checked by removing something cut into surface. Unless surface is extremely oxidized, treatment will only use a couple of microns of the coating. Final protection is by any quality wax (not wax/polish combo) Re-apply wax yearly (or more, based on your UV exposure)
Your detailer is clueless. Find a boat service outfit near you to hire it out if you need it done. This is routine on fiberglass boats.