Heima, yes I think Forscan will work, and other brands of apps might not.
Anti_Climax, being near Phoenix with little A/C can't be good. Hard to diagnose of course, but this is the interweb, so I'll give it a shot: Sounds like an obstruction in the refrigerant lines is reducing cooling ability. Or a bad feedback sensor (pressure, temperature). Both might cause cycling.
I was told last year that my A/C compressor was causing an intermittent short-to-ground from the HV battery. A dealership told me that. I chose to not spend a bunch of $$ replacing the compressor unit, ignored the issue, and the dashboard warning never came back. These things can be mysterious.
"Giving up the fight" as I & some others have done, reminds me of so many folks who have told me "Never own a complicated German car past the warranty period." Seems that advice applies to about any vehicle make these days, or one can take the risk of repairs themselves. Owning vehicles is a crap-shoot.
Another old rule is to sell your car either at the 3-year point, or the 12-year point only, to minimize the risk of not getting your money's worth.