From yesterday Diablo 3 has changed to only offering two resolution options.
I have tried switching between windowed, fullscreen, and fullscreen (windowed) mode, reseting all to default from the battle.net app client, checking permissions, and trying to use the command line argument to force a different resolution, none of that works.
macOS Monterey 12.4
MacBook Pro (13-inch, M1, 2020)
Apple M1
16 GB