Sorry for not giving an answer, but I have no idea what may be going wrong with your VR installation. For me, everything works as intended in SteamVR, and I know from many Quest users, that they have no issues, too.
As you may know, the VR-mode in the alpha, is only for demonstrating "it works". The non-VR mode is to show the new functions, and the VR-mode is very limited, like the VaM developers wrote. You more or less can't do anything than looking around and maybe doing some very basic stuff.
Maybe this is what you are experiencing. I can't really move around, too. The whole alpha is only a very first proof of concept.
I have no idea what those "screen tearing" might be or looks like.