Like many users, I have also been having Bluetooth issues since upgrading to Monterey, I have updated all the MacOS as much as I can and I'm on 12.4 but with every version upgrade, nothing is fixed and Bluetooth will drop several times a day. Sometimes it re-connects back straight away, other times, I won't be able to connect for 5 - 10 mins. I have Activity Monitor on all day and when Bluetooth drops, there isn't any excessive CPU or memory usage. Sometimes, when my Mac is busy doing Time Machine backups I see the Bluetooth issue more but there doesn't seem to be any pattern. Have tried everything to reset Bluetooth, delete pref, remove/add the device again, reset NVRAM and SMC and nothing works