Hello Simon Leung
Yes, if you have assigned a public IP address to an Azure Virtual Desktop (AVD) instance, you should be able to ping the public IP address from another machine on the internet.
To do this, you can open a command prompt or terminal on the machine you want to ping from and enter the command "ping [public IP address]". For example, if your AVD instance has a public IP address of 123.45.67.89, you would enter the command "ping 123.45.67.89".
Note that if you are unable to ping the public IP address, it could be due to network security restrictions, firewall settings, or other network configuration issues
If this my response does answer your queries, please accept the answer as a token of appreciation.