I installed Real VNC Server

sudo apt-get install realvnc-vnc-server
sudo raspi-config
Interface Options > VNC > Enable

However, when I run VNC Viewer and connect I see a grey screen instead of the Pi Desktop

This is how I resolved it:

sudo systemctl disable --now wayvnc
sudo systemctl enable --now vncserver-x11-serviced
systemctl status vncserver-x11-serviced

It now works.