I'm trying to pair my Logitech G603 Bluetooth mouse with both windows 10 and Ubuntu. I followed this and this without success. I think that the problem is how the export of the Key from windows, since from chntpw I get different values than what I get from Windows itself.
It sounds that with Linux 5.9+ there are some "issues" with the Bluetooth stack. Removing
[IdentityResolvingKey] Key=... fix the issue of bluetooth mouse that after the reboot not connect anymore.