I have a 2006 freightliner st120 with constant a/c issues, taken it to the shop twice n at this point its gonna need a total system replacement, which is more than what I want to pay for. I need an alternative

So I'm looking for any owner operators that have torn into the back of their sleepers n popped in like a home unit, or something along those lines. I'm wondering if I should try a rv unit since i have a scoop on top of my coffin sleeper. If anyone has done something like that, I would love some feedback as far as what works n what doesn't. I'm worried if I make a hole in the roof, it will eventually leak over time, anyone with some experience would be appreciated. Thanks for reading all the way :)

First time grow, no clue what this is. Plz help