I also had this problem of flickering when I used the fake dtoverlay=vc4-fkms-v3d . Now that I am using the “original” OpenGL driver it is solved for me.

@sdetweil wow I was not aware of all old events also being sent and parsed… from 5+ years ago. That’s a lot of entries… (more than 1500 only for my main calendar)
I sent the log via eMail to you.

adding an address: "0.0.0.0",did it, I can see the black page of MM in my browser… thanks a lot for your help. Now I’m even more waiting for my mirror and screen to arrive…

I use crontab and added
@reboot tvservice -o to deactivate hdmi output on start. You can activate it on demand (as I do) or maybe after 60 seconds