I had this issue with my Camplite 6.8 Truck Camper. I installed a 6mm thick Commercial Rated LVP Click Lock Flooring right over the existing Sheet Vinyl. I glued it down. It looks fantastic and solved the problem 90%. It is flexible but fairly rigid. I am happy with the result. I finished the job with plastic trim molding to keep with the no wood idea even though I found that the OEM molding is paper covered wood.