As from my pain and looking up this issue this has been a bug for 1-2 years already. Will this ever be fixed?
In summary, when you change the aspect ratio of a Camera Card it changes the dimensions of the card and not the camera. All live cameras that are 16:9 come in stretched to 4:3.
Default LIVE (box is 16:9 but camera feed is just clipped off the container box)
When you type in 4:3 it unclips it. The aspect ratio doesn’t change in either.
It looks the same when you look at the entity.
When you switch to AUTO view it looks correct. This is how it should look like.
However auto is not live, auto are still images that get updated every 10?sec.