We are aware of the issue with forwarding USB camera from macOS-based client and we will be fixing it. Please watch out for the fix in a future maintenance. If you would like to check the status of this issue, you can do it here: https://kb.nomachine.com/TR05S10262.
Have you tried forwarding any other device? If not, please try to forward something else, like a Keyboard or USB stick, and write here whether it works or not.
The mouse should ‘freeze’ on the local side (in your case client-side), it’s normal because every USB device during forwarding is disabled on its host machine, and becomes operational on the machine where it’s forwarded to (in your case forwarded to the server). This is what seems to be failing.
You could also check the network latency (ping time), especially if the devices are in different networks.