Here is how to set Excel file read-only when using in MS Teams, OneDrive, or SharePoint. Those environments are different in the possibilities to change Excel file settings. Here is a quick walkthrough.
Category: MS Teams
How to sync MS Teams files with local OneDrive folder
If you’re interested to use your MS Teams files like you usually would in File Explorer, then here is how to sync with the local OneDrive folder.
How to restore deleted MS Teams channel
If you are here, then I suppose that it is not so intuitive to restore the deleted MS Teams channel.