It won't work if you don't have on-premises pass-through agents registered to the tenant. Can you make sure that these are registed? https://learn.microsoft.com/en-us/azure/active-directory/hybrid/how-to-connect-pta-security-deep-dive
Do you see an error when you enable it? Or does it turn on successfully with no error, but the manage groups is still unclickable?
Make sure you try with a global admin account.
If you can reproduce this issue please send me a screenshot or video to AzCommunity@microsoft.com and I will get someone from the product group involved.