When going to the Monitor > Machines page I am not able to see the machine and machine group pivot.
Check the documentation to see the required version of MicrosoftFlowExtensionsCore
Check the version of MicrosoftFlowExtensionsCore in your environment
Go to Solutions > See history
Look for MicrosoftFlowExtensionsCore in the search bar and check the latest version
There's a possibility that MicrosoftFlowExtensionsCore will not appear in your history in this case reach out to your support which will check the version for you.
If you have a version older than the one required in the documentation it means the dataverse solution for the selected environment does not support machine and machine groups.
Wait for the update to happen or contact support in case it doesn't.