2008 Vue XR 3.6L V6 212k miles A/C not working after vacation

Greetings,

My family left on a 3 week vacation this June and returned to our parked 2008 Vue. I turned it on while sprucing it up, but noticed that when I turned on the A/C there was a hissing sound behind the dash that I didn't notice before. I tested again and felt for the air temperature to change, but it felt barely cooler than the ambient air and sometimes hotter, like it was trying to turn on but then couldn't. If I turned off the A/C (indicated by the light on the dash turning off) the hissing stopped.
After another check, it sounds like the compressor is trying to do its work, but just warm air blows.
Approximately 9 years ago there was some A/C work done, and then 3 years ago we replaced the compressor. My guess is a hose cracked in the June heat while we were away and broke when I turned it on.
I did however check that there was pressure in the A/C lines, and there was, but I don't have the correct fitting to measure what the pressure is.
Any info on how or where to continue with this fix would be appreciated.