ETERART Heavy-Duty Aluminum Foil Duct Tape - 2" x 20 Yds, High-Temp Seal for HVAC, Dryer Vents & Insulation, Stops Air Leaks & Resists Extreme Heat for Home Repair, Silver

Rvs will just be hot, but you can probably help a little. If you have or can use an air compressor you may be able to blow the coils out. It looks like your unit is very dirty inside. You may need to take the rest of the plastic cover off, your coils will be between the sides. Also while all the plastic is off get yourself some of this tape https://a.co/d/004wXEAA Remove the old tape and apply new tape to ALL gaps. Without even seeing it I can tell you that there is old tape peeling and broken letting cold air into the ceiling instead of into your vents. There will be gaps around the ductwork and around the whole ceiling. There are YouTube videos but you probably don’t need them.