I’m also having issues connecting my H90 to my M1 MacBook Pro (running Monterey 12.0.1).  I get as far as entering my passkey, then it searches for the device, doesn’t find anything and then the bluetooth on the H90 turns itself off.  Also tried many times with no success.

I’d read the statement where it’s noted that there’s sometimes issues with Bluetooth Midi on Monterey and to upgrade to Ventura to try and resolve the issue, but sounds like there’s still issues with Ventura as well then.  I’m waiting for a new external hard drive to arrive so I can back up my system as it stands before upgrading to Ventura to see if that fixes it for me.