Yes, I have put the yoke in Single-Eng. Prop and the FS2020 settings also, but still the problem persists: I only have a limited range of control on the vernier knobs.
I learned to create a Cessna 152 profile from scratch, using only the vernier knobs, with the same result: only a limited range of control.
I also have a problem with the ailerons, despite setting the sensitivity to 0, and having a linear ‘curve’ or rather a straight line on the settings graphics, the yoke in the Cessna 152’s cockpit still responds non-linear, it still seems to have a respons curve.
The General Options: Fight Model is Modern (Realistic)
When I put the yoke in Training mode, it displays the linear and full range of all the controls configured in the default Single-Eng. Prop profile.
In X-Plane 12 which I bought at a discount in the latest Steam sale, I had to set up my own controller profile, and here everything works as expected: vernier knobs have 0-100% range and the yoke controls the ailerons linear.
So somehow I think FS2020 is smarter than me 
while I like to have full control over any and all settings.
This is what is shown on the Settings screen with my custom profiles, copied from the default Single-Eng. Prop. The black vernier knob is pulled fully out, the red one is fully in, the start up situation on a Cessna 152, notice the throttle bar isn’t at 0%, the mixture bar isn’t at 100%. And the indicated range is fixed at this 25% or so.
I have found and opened the Cessna 152 custom profile .xml files in the Steam/UserData folder, and noticed no real difference in relevant sections of settings between mine and the default profiles from the Input folder.
So if somebody can share his custom profile’s .xml files, I can compare, learn and configure.