It would be great to be able to zoom out to a monthly view in order to plan longer term projects

I found Day and Week Views - what about monthly or quarterly

Please allow zoom out to monthly to allow overview on long projects.

I see the calendar option, but it only shows the weekly view.

change the days 10 years 0-20.

I would strongly suggest you make available the option to have timelines be broken down yearly and the years be broken down quarterly. I have many projects that scan across multiple years, and your current layout does not facilitate a comprehensive view - to the point i am going to have recommend using different software for my entire company.