The mouse smoothing also results in higher input lag. That is because the input has to get buffered. Some people will associate that feeling more with higher input lag or an amount of input lag that is disproportionally high for the framerate, so I searched for that and found serveral reports.

This has been ignored for over a month now and nothing has been fixed. When can we expect this to get addressed?

That there is a camera rotation speed limitation is horrible in the first place, but that the limit increases with increasing mouse sensitivity is absolutely inacceptable. Also the "software cursor" option does not currently work. Changing the windows mouse sensitivity setting should not result in a different aiming sensitivity when it is disabled, but it does. The camera rotation speed limit must be removed and replaced by a character/turret turn speed limitation like in most other games (Battlefield, PUBG,...). The camera should always move freely without any limitations.