Camera locked downward and teleporting up/down when moving

Having this exact same issue. I don't know how to fix it. Been days and have gotten no response.

Question. 
You said it happens with "Moving or Turning"
1. By moving, do you mean, if you were to get it off of looking straight up or down, that by pressing ONLY Keyboard keys, it would reset and snap back down/up?
If so, does your Keyboard have 1 or more USB connections, and does it have software that allows you to map functions to keys.
Or does your mouse also have and app to remap functions to mouse buttons (Razer Synapse is a horrid programme, please make sure you have the latest Synapse 3, Synapse 2 and lower dont even have access to their servers anymore...)

If its also ONLY when you are in BF6 && (AND) In-Game state, it might be an issue with how BF6 and your mouse are trying to implement a Mouse Lock function. That COULD be a driver issue, but you did mention you used DDU to remove SOME drivers for the GPU but NOT for the mouse. I would suggest DDU removing mouse drivers (ensure you keep default drivers for basic PAP capabilities) one at a time, since you are using 2 different mice, and seeing if removing Mouse A's Drivers allows mouse 2 to work without issue, and if it still doesnt work, remove mouse 2's drivers and see if either mice work again.
If neither work again, re-install Mouse 1's Drivers and try both mice again, and if not, install Mouse 2's Drivers and test.
If that doesnt work, then I cant see it being anything on your end, it would have to be how BF6 handles your mice explicitly.