If I read your problem like that, there must be something special going on.
On my Smartphone I have a spirit level as an app, how it works exactly, I have no idea.
When I was still working in the assembly, a long time ago in the meanwhile, I also saw an electronic water path, after researching exactly how it worked, it turned out that there was a crank in it that operated a precision potentiometer.
Space was needed for that and there is certainly not in my smartphone.
The TomTom Start 20 that I have here, the screen of which is also rotatable, since there is more or less a fixed docking system on it, it is necessary, otherwise you cannot place it properly on a window.
Which part is now responsible for determining the position of the screen, I have no idea.
Maybe Mr. Google knows an answer to that and otherwise open it up to see if a special part has been mounted on the printing location.

I did a quick search with Mr. Google and soon come across a Dutch site where some information can be found.

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If it were something mechanical, I can imagine that in a certain position strange values ​​must be processed in your TomTom, because something freezes and as a result your device freezes or possibly even resets.
But it all remains guesswork until we know the right part.