Thanks for the posting, Christian! While SharpTools has a calendar integration with an agenda view that blends in with a seamless style, there is a feature request for a monthly view at the following link that you can cast a vote on (and comment to bump the thread):
Community feedback is a key part of what we work on and this particular request hasn’t seen a lot of votes. Perhaps you can also help contribute to the feature request thread by describing what use case a monthly calendar view solves that the calendar agenda view doesn’t.