The new Arduino IDE 2.0.0-beta.6 is non-functional for me. (as all previous betas have been) I'm on MacOS 11.3.1 (Big Sur) on an 2015 MacBook Pro (Intel). I'm a long-time Arduino user with many existing sketches, board packages, and libraries installed.
However the new IDE app is totally non functional on startup with the error:
"Request loadSketch failed with message: 14 UNAVAILABLE: No connection established"
(see image below). The sketch directory does exist, in the standard location ($USER/Documents/Arduino).
I have given the Arduino IDE both "Files and Folders" and "Full Disk Access" in Privacy Preferences.
The problem appears to be some sort of communication failure between the GUI and a backend process. Attached is a zipped file of the application output when invoked via commandline "/Applications/Arduino IDE.app/Contents/MacOS/Arduino IDE"