A/C issues
As for the AC diagnostics showing 21, that sounds incredibly high. If someone did it at home, I’d guess they forgot to take into account the ambient air temperature while charging the system. Since you went to a REAL AC place, they probably didn’t overfill it because they know an overfilled system doesn't cool well and will eventually blow the seals.
IMHO, the best way to determine if the AC is working well is to test the vent temperatures. That is what you care about,right? The temperature of the air leaving the vents? You may also want to know the temperature at the EVAP sensor.
Yes, that picture has been known to drive some people off the deep end.






