Hi @Emily ,
According to my research and testing, unfortunately there is no JSON that can achieve this. What is currently possible is to filter the view and only display the events of the specified month. However, clicking on the calendar still displays the current month. This is by design.
If you want to implement this function, it is recommended that you go to Partner Center for function development.
Or submit feedback about this issue. This is the best platform to let us hear from you and make our products and services better for you and others. Microsoft values its customer feedback and a lot of features have been developed and suggested by customers via feedback. Your feedback is also very important. I am sure SharePoint developers are working on this. Our Product Team is in-charge of the site and they are constantly checking the comments and feedback from our customers.
Hope this helps.
Your recognition is my honor. :-)
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