LinuxCNC Debian Buster with X11VNC

I used to mirror the screen of my LinuxCNC workstation running Jessie with X11VNC to my main computer. This worked great and I could use both maschine in parallel without starting a new X11 session. It was very performant and worked great.
I now have setup a new machine with 2.8.1 and Debian Buster, but the X11VNC package (an extremely old .9.1.3 does not seem to work any more, creating extreme load for X11 process.
The .9.1.6 supllied with the latest debian 11 "bullseye" works with a testing system great, however there is no LinuxCNC version available for this.
Any other solution to mirror screen, keyboard and mouse ? Import would be that both session run in parallel.

Xrdp

VNC, or TightVNC, or any of the other remote desktop apps.
X11 is getting dropped completely and Wayland is replacing it,.

Is any of this alternative able to mirror so the session can beseen and inputed on more than one device? (and is not as evil as teamviewer )

Not xrdp
This opens your own User.

Rilke1999 wrote: The .9.1.6 supllied with the latest debian 11 "bullseye" works with a testing system great, however there is no LinuxCNC version available for this.

You could try installing the LinuxCNC kernel and application .debs on Bullseye. There is a pretty good chance it will work.

If not, there is probably a preempt-rt kernel available for Bullseye, and then you can try the LinuxCNC .debs again, and if that doesn't work, build from source.