@soulplan Hello, you can currently achieve this by modifying cg_fovScale instead of cg_fov. Set your cg_fov to 65 (console default) and then adjust cg_fovScale to your likings. This way your ADS field of view (and sensitivity) should be the same when zoomed in and zoomed out.
We will implement this as a feature in a future update of Plutonium.