When I set the lock to AR, the model is not 100% locked, it has a small rotation margin, I think the model should remain locked in rotation as well.
Which AR mode are you using? Would you be able to post a screen recording?
In orbit/zoom and move/look mode, right now I don’t have a screen recording, by the way I want the surface edge to appear, is there any way to make it appear?
Looks like you’re using “Rendered - AR” display mode. In rendered surface edges aren’t shown by default. You can either use “Shaded - AR” or tweak the edges visibility in Settings > Display when you’re in AR mode.
I also recommend you checkout the WIP iRhino which has some improvements to the AR experience.