I test weekly and Our Tenant does not seem to support the "Required App" Grant as of yet. I have set up a policy similar to csmithscf , However Teams does not Support the "OR" qualifier in CA. It seems to work but the Documentation specifically calls out that it is not supported. Therefore I only have a Small test group on that policy.
https://docs.microsoft.com/en-us/azure/active-directory/conditional-access/concept-conditional-access-grant#require-app-protection-policy
Note
Microsoft Teams, Microsoft Kaizala, Microsoft Skype for Business and Microsoft Visio do not support the Require app protection policy grant. If you require these apps to work, please use the Require approved apps grant exclusively. The use of the or clause between the two grants will not work for these three applications.