I’ve spent 100 hours on Forza Horizon 6 using Dualshock 4 and Moza R3. I'm not claiming that this is the best wheel setting, but this is by far the most comfortable / controllable that I am able to tweak.
Please use these settings as a baseline and tweak it to your liking. I’ll be providing both Moza Pithouse and In-game settings that feel the best for me.
Table of Contents
Moza R3 Pithouse Settings for FH6
Important #1: Start in system settings, turn on Supports beta version updates.

Important #2: Go to Experimental Function:
Make sure you are using Version 1.3.9 or higher.

Make sure to turn on Base Forza Compatibility.
Now go to Wheel Base settings:
Maximum Steering Angle: I personally use 720 with a 14inch wheel, good steering angles for forza horizon 6 are between 540 to 900.

I use Soft Limit stiffness because I hardly reach the 720 degree, if you’re using 540 you can bump this up to 3 or 4. This introduces a feeling of wheel fighting back when you’re about to reach your max steering angle (bad for drifting).

For Handing Feel, I have my Game Force Feedback Intensity at 62% when i cruise or relaxing drive around the map, and I have it at 98% when I race or drift. For the Maximum Output Torque limit, I max it to 100% so my wheelbase outputs max power when it needs to.

For Force Feedback Reversal, I have 0% Force Feedback Interpolation and 2 tick of FFB Center Deadzone Compensation, this introduces a smooth point when you’re going straight which helps you notice the center of the steering wheel better.
I set gear shift vibration intensity to 0 because the effect is distracting. (Personal Preference).
I have Maximum Wheel Speed at 100 which is the default wheel speed number.
For Base Force Effects and Game Force Effects, I set them all to 0%, I don’t want my wheelbase to add any unnecessary effects to my wheel when playing the game, I want pure raw Forza Horizon 6 force feedback effect directly to my wheel.

For FFB Effect Equalizer I set Sensitive steering at 10. Forza Horizon 6 is a simcade, these effects are not as realistic as a sim racing game.
For Base FFB Curve and Miscellaneous settings I have them all at default.
Moza R3 Forza Horizon 6 Settings
These are my in-game settings that I use for Racing, Cruising down Japan touge road, and drifting.

Everything inside these settings are pretty much self explanatory:
My Steering Axis Deadzone Inside is at 0, outside at 100, so that the steering input from my wheel to in-game is true 1:1 with no delay.

I set my Steering Linearity to 25 and Steering Sensitivity to 1.0, for me this really makes the handling feeling and responsive feeling for all cars very smooth, especially when turning in a hairpin, curvy road, wavy road, it handles all those turns easily.
My Off-Road Feel Scale is at 0.1 because I don’t like the vibration feedback to the wheel. I found that shaking annoying and unnecessary.
Besides that I have everything else as default. I really hope these settings can help my fellow Moza R3 owners that are struggling to find a good setting to enjoy Forza Horizon 6.
End of Guide.
