Unstable Sidecar connection

As of late, the sidecar connection between my MBP and Ipad Pro is very unstable. It used to be all good, having the Ipad as an extra screen.

I now often have a black screen on the ipad, or the connection takes some time to complete and then there's a time-out. Sometimes with the black screen I still can enable the Sidebar and touchbar emulation on the Ipad. At that point the Displays preferences pane indicates the ipad is properly connected.. but the ipad doesn't show an OS desktop.

I've already tried the same tips everywhere on the internet: toggle the mirroring options on and-off, toggle handoff on and off.. the only thing that works is to restart the MBP.. But not long after that the sidecar connection gives up on me again.

thx

pascal