Oo, one thing I can see maybe I can help with:
It looks like you hold the thing too far forward, it should rest pretty comfortably on the side of your jaw. For my viola I think its a little more forward but still at a shallower angle.
You probably actually know this since the second video looks right, but whatever, I'm just trying to leave a comment
I find there's so many more rules that are necessary in general to get a proper sound compared to guitar where you just pick some strings and that's that... long journey ahead for me!
I don't know why but I struggle to hold it stable like that, I even bought a little shoulder rest and it doesn't feel quite right, maybe I just need to mess around with the placement more.
Yeah the shoulder rest helped me big time. Wrong way round or something daft like that? Fat side attaches to the side of the chin rest thingy. Violins always feel weird and small to me no matter what though. No going back from the viola! We should become mortal enemies
LOL, funny you say that I tried switching it both ways round and even watched a video for attaching the rest, tried angling it a few different ways, raising/lowering it etc. In the end I don't use it that much!