Unstable bluetooth connection with Logitech M535 mouse

Hi

I got a Logitech M535 bluetooth mouse on my 2012 retina macbook pro (High Sierra 10.13.3).

It's a good mouse, apart from this:

Whenever the computer returns from sleep (after a while), the mouse takes a looong time to reconnect to bluetooth and work again.

The light on the mouse is blinking (it's trying?)

I move the mouse around while clicking away, but it doesn't help.

I have made sure that the bluetooth settings are as adviced by logitech. No luck.

I have tried disabling and re-enabling and reset bluetooth and the mouse connection. No luck.

Other problem:

The mouse is "jumpy".

Meaning: from time to time, the signal seems to shortly get lost/reset or something, so the mouse cursor jumps from one point to the next on screen.

I'm not sure if this is a mouse/hardware/software problem, or a OS/bluetooth problem

What to do?