Hi,

via Windows Policy it is possible to restrict the access to multiple Networks.

If you have a domain connected computer and want to prevent using a second network interface then set the policy

Computer Configuration/Administrative Templates/Network/Windows Connection Manager

“Prohibit connection to non-domain networks when connected to domain authenticated network”

Or if you want to control it more in detail use

“Minimize the number of simultaneous connections to the Internet or a Windows Domain”

“Allow simultanoues connections” => Allow all traffice
“Minimize simultanoues connections” => Any new internet connection is block if a connection exists but User can still manually connect to any network, e.g. WiFi or cellular.
“Stay connected to cellular” => Similar to “Minimize simultanoues connections” but user can connect to WiFi and Ethernet and no routing is possible
“Prevent WiFi when on Ethernet => This prevents WiFi connections is an ethernet connection is already established

See also: How to prevent the driver installation for a specific device.

Michael