Unexpected changes in display size during movies


I have a few challenges with the display size with the U5:

a) according to the sources (Amazon on U5, Netflix through Fire stick , HD TV through HDMI) through Firestcik) the display size can range (a lot). Isn’t there a way to systematically adjust to scale the image size to a given format, e.g. 16/9, so that it fits the screen? I’m happy to change resoultion manually if the scaling produces poor results. I use VLC to play movies, and there are settings in VLC to adapt the zoom/scaling. I often need to slighly move the projector closer/farer from the screen and adapt the size in VLC to have the max display size. Are there ways/advices to properly handle this?

b) Weirdly, in some movies, the display size changes several times during the movie. After doing a), the display size is a good as can be. But then, in some specific scenes the display size changes, and the display size get bigger than the screen. It swicthes back to normal dispaly in the next scene. So it’s not happening at random times, it’s always changing specifically at the beginning of a scene, never in the middle of a scene. I’ve never had such a behaviour with the U4. Again, I couldn’t find a set up to address this.

One more note: This is rather new behaviour. I cannot swear it at 100%, but this might have started after the last software update.

Any advices on a) and/or b) would be welcome!