Hello there, My name is Indhurani, I'm sorry that you are experiencing this issue, and I will try my best to assist you.
Microsoft Teams is still relatively new and is still in the process of adding new features. Monthly view options may be added in the future, but as of now, there is no monthly view option available.
I would suggest submitting feedback through the Teams app by selecting the Help button at the bottom lower-left of Teams and then choosing to Suggest a feature or Give feedback to tell us what you think. So that they can include the additional features that you want to see in future releases.
Please refer to the link below to the thread where similar issues were talked about: https://answers.microsoft.com/en-us/msteams/for...
Please let me know if you still need further assistance.
Regards,
Indhurani