That is the nature of FFB. DCS has native FFB support and each module has its own unique implementation.
If you enable sticky spring, you will lose the entire dynamic aspect of FFB (if the aircraft has such, aka non-FBW) including trim movement.
Don’t try to set up the rhino for a specific aircraft outside of the sim. Do it while the sim is running and you are loaded in the aircraft.
As a simplified explanation, if DCS says “set %85 spring strength”, that %85 is not related to the maximum force your joystick can output, it is related to the maximum force you have configured in vpf configurator.
So if you had your slider at %50, and DCS said “set %85”, that actually results in %85 of %50.