Family Link always allow phone

I've been looking into this and reading articles for the last hour or so, and haven't come up with anything. The simple version of what I'm trying to do, is when my kids are grounded or at school that I'd like to turn their smartphones into a dumb phone. They need to be able to call my wife or myself in case of emergency, call specific contacts if we're not available, but not chat with all their friends. If someone can point me in the right direction for where these controls are located I'd very much appreciate it. The 'Phone' app is not listed in FamilyLink under the apps I'm able to 'always allow' and there's no way I can see for me to limit calls to specific numbers. I'm totally open to third-party apps if there's a paid solution to this out there.