The "direct capture" option is not working when running VNC Server on Raspberry Pi OS with the KMS driver (vc4-kms-v3d). The Fake KMS driver (vc4-fkms-v3d) is not affected.
Enabling it will cause VNC Server to send a blank screen and you will lose remote access to the VNC Server. Our development team are investigating and hope to make a fix available in the near future. This issue affects all current versions of VNC Server, 6.9.1 and earlier.
If you have enabled direct capture with the KMS driver enabled and need to disable it, you can do so at the command line by connecting to your Raspberry Pi using SSH and running the below commands:
sudo sed -i '/CaptureTech/d' /root/.vnc/config.d/vncserver-x11
sudo vncserver-x11 -service -reload