I think the zoom sensitivity has been re-worked since I last checked, working on updating it now.
Scratch that, the sensitivity was bugged until I did a fast travel.
The Sniper 2X is the first zoom of the long range scope, but 2X is not really correct so I've renames it to what it actually is. The FOV was also wrong.
Close and far etc in the game uses the same FOV and just changes the camera distance, so calculations do not change.
I tried the mod, but not getting it to work, FOV stays the same.
Also the game wasn't able to load my save, so I had to start over!
All the Assassin's Creed games released before Valhalla are poorly optimized for mouse and their sensitivity fluctuates a lot depending on FPS, camera tilt and distance.
So none of them can be added unless there's a specific fix for this.
I tried this game again now, as I first looked at it for the launch. Got the sensitivity better by enabling FPS Limit and lowering it so the FPS was stable, but still the sensitivity fluctuates depending on how you tilt the camera and how close it is. So this game (and any other Assassin's Creed AFAIK) is not possible to add.