Thanks for the detailed answer.
You're right, only the more advanced videocameras will allow to you record at different fps, either higher or lower than 24fps (8, 12, 18, for example). Not sure about your GH7, though.
But as you mentioned, you can play around with a lower shutter speed to break the 180º rule. Try 40 or 30 instead of the usual 48 or 50 and see what happens. Can't lose anything for trying, right?
I don't mean to be rude, but it's hard to make innanimate objects feel "cinematic". We'd get a much better feel of the cinematic vs. video aesthetic you mention by recording human movement.