I have been unable to find this exact issue, but a similar one with no answers at Ubuntu 20.04 cannot connect to paired bluetooth mouse after reboot
After reboot, Ubuntu 20.04 doesn't automatically reconnect keyboard. Selecting "connect" it just spins and never connects. The only way I get it to work is by removing the device and re-adding it, then it works perfectly, until the next reboot.
Not sure what all is needed, but here is my output for sudo dmesg | grep -i blue:
[ 4.025351] Bluetooth: Core ver 2.22
[ 4.025362] Bluetooth: HCI device and connection manager initialized
[ 4.025363] Bluetooth: HCI socket layer initialized
[ 4.025365] Bluetooth: L2CAP socket layer initialized
[ 4.025367] Bluetooth: SCO socket layer initialized
[ 4.048577] Bluetooth: hci0: Firmware revision 0.1 build 26 week 11 2020
[ 4.694442] Bluetooth: BNEP (Ethernet Emulation) ver 1.3
[ 4.694445] Bluetooth: BNEP filters: protocol multicast
[ 4.694450] Bluetooth: BNEP socket layer initialized
[ 7.238314] Bluetooth: RFCOMM TTY layer initialized
[ 7.238317] Bluetooth: RFCOMM socket layer initialized
[ 7.238319] Bluetooth: RFCOMM ver 1.11
[ 2763.520290] hid-generic 0005:046D:B33B.0010: input,hidraw9: BLUETOOTH HID v0.29 Keyboard [Keyboard K780] on 04:d3:b0:cc:00:6e
[15815.762564] hid-generic 0005:046D:B33B.0011: input,hidraw9: BLUETOOTH HID v0.29 Keyboard [Keyboard K780] on 04:d3:b0:cc:00:6e
[16937.761068] hid-generic 0005:046D:B33B.0012: input,hidraw9: BLUETOOTH HID v0.29 Keyboard [Keyboard K780] on 04:d3:b0:cc:00:6e
[24610.784457] hid-generic 0005:046D:B33B.0013: input,hidraw9: BLUETOOTH HID v0.29 Keyboard [Keyboard K780] on 04:d3:b0:cc:00:6e
[57059.287394] hid-generic 0005:046D:B33B.0014
I do not have Blueman installed, not sure if that would even help as the above-referenced user had no success with similar issue for Bluetooth mouse.
Logitech forums have no such issue. Any advice would be helpful as I am able to connect by adding the device after each reboot, but it would be better if it automatically reconnected, even if just with the "connect" button.