Wax residue won't come off! How to remove?

It sounds to me like you have oxidation from the sun. No matter what you do to the camper if you don't buff it off it will look the same. This is the best kit on the market and I have used it many times as I used to do this for a living.  You can do it by hand but I highly recommend a buffer.  I recommend the cheapest random orbital you can find.

https://www.amazon.com/s?k=polish+buffer+machine&crid=G1V9RGVAOBES&sprefix=polish+buffer%2Caps%2C108&ref=nb_sb_ss_ts-doa-p_3_13

https://www.amazon.com/Meguiars-Marine-Fiberglass-Restoration-System/dp/B0000AY4YT/ref=sr_1_6?crid=1D6ESXNUR1DR8&keywords=oxidation%2Bremover%2Bfor%2Brv&qid=1705096599&sprefix=oxidation%2Bremover%2Caps%2C104&sr=8-6&th=1

If you want to skip two steps then try this.

https://www.amazon.com/Meguiars-M6732-Marine-Step-Compound/dp/B00029CYRG/ref=sr_1_7?crid=1D6ESXNUR1DR8&keywords=oxidation%2Bremover%2Bfor%2Brv&qid=1705096599&sprefix=oxidation%2Bremover%2Caps%2C104&sr=8-7&th=1