Thanks for another wonderful suggestion @muneer
I have personally implemented a low code approach using both Full Calendar (more like full code) and color calendar (also a full code approach but far easier to set up)
I would imagine throwing either of these into a webviewer and passing messages back and forth would be an excellent addition to any app, though it would take some work to implement. I believe @domhnallohanlon has posted a thunkable native made calendar
in the past.
^^^ airich911ei remixing the above mentioned app could be the start that you need!