First of all, remove Time.deltaTime from your mouseX and mouseY calculations. Mouse input is already frame dependent. So multiplying by Time.deltaTime actually messes up the speed.
The actual speed you rotate is controlled by your sensX / sensY factors. If you want to limit how fast the user can actually rotate, regardless of set sensitivity (which would be really weird) you could clamp mouseX / mouseY to a certain value. Note that this limiting value should be multiplied by deltaTime.
Here you can see at my script on player as an example which also adding a bit of smoothness aka inertia, because without it you would feel turning much worse at low (less than like 40) fps, and even on high without it on high speeds you can feel some nausea.
Generally, less FPS you got, more smoothness you want, but I didn’t bother to autoadjust it, just let the player choose the value.
And if you want to clap the rotation speed, just clamp the mouse input vector for example, tho I am not sure if you really want it. To make rotation feels okay it should be sufficient to remove that deltaTime, and if you want more smoothness implemeint something like I did.
Oh u used the same code as mine i think u should check the senX and sensY and lower the sensitivity it should be in the inspector and under the code normaly for me it lowers the speed. Hope it works