Okay, so I have searched a bit and found at least a temporary solution that works for me.
(1) First find your bluetooth mouse physical address, e.g. by running
hcitool con in a terminal.
(2) Then open the file /var/lib/bluetooth/XX:XX:XX:XX:XX:XX/ZZ:ZZ:ZZ:ZZ:ZZ:ZZ/info and add the following lines
[ConnectionParameters]
MinInterval=6
MaxInterval=9
Latency=0
Timeout=216
(3) Finally, reboot.
I guess those values depend on the bluetooth mouse, but at least for my Logitech MX Master 2 it works. I know this is a very inelegant solution, and maybe somebody else has a better idea, but at least I can use my BT mouse again.
BTW, this is based upon:
and the last comment from