There is a workaround for you, this also works for any work profile as well. Install a VPN, it can be anything, maybe even InviziblePro on fdroid or something that acts as a VPN. Then in android settings, in VPN settings, deny all internet access that is outside of the tunnel, then in the VPN app, just keep the VPN tunnel turned off. So now no internet will go through for that user profile or work profile.