Get the model number and year of your AC. Then go to YouTube and do a search; i.e., filters, maintenance, not cooling COLD.
I had issues on a new 2015 model. I dropped the inside cover, got the numbers and called Dometic's help line. Unfortunately or fortunately, ( under warranty ) my unit was replaced. "Unfortunately", because they tore my brand new RV roof and full roof ( under warranty ) was installed.
Go back on the search app of this forum and search as well.
The Dometic's have mostly sealed units. Might just be bad.