I've got a Logitech V270 bluetooth mouse that has worked fine in the past with previous versions of Ubuntu (and other flavours of Linux, and [even] Windows). However, when I've paired it with my HP Elitebook 850 G6 running Ubuntu 20.04, the mouse stops moving the cursor when I leave it for a few seconds. Sometimes a click will wake the mouse, other times it needs a scroll on the wheel, but if I can wake it it works perfectly ... until I again leave it to type for a few seconds.
To be fair, I've never used the mouse with this computer before, so I have no idea if it would happen under Windows, but it worked perfectly with my other HP Elitebook 850 G3 running Ubuntu 16.04.
If anyone has any ideas where I could start looking at, I'd be much appreciative :)