You can uncheck Automatic Set Speed Offset. Then set right scroll wheel for current speed. Then you can manually control speed with the right scroll. However, every time it passes a speed limit sign it will reset to speed limit. You gotta watch it. After all it's FSD (supervised).
The reason I use auto speed is it works better than manual speed in my situation. I used manual speed with v12.2.1 but it didn't work well.
With auto speed I see the following:
When speed limit is 20 mph, FSD never goes past 20 mph.
When speed limit is 25 mph, FSD goes up to 32 but not always. A lot people go 35 mph on that road.
When speed limit is 30 mph, FSD goes up to 37 but not always. A lot people go 35-40 on that road.
When speed limit is 40 mph, FSD goes up to 45 mph but not always.
Most people go 45-48 on that road.
When speed limit is 50 mph, FSD goes up 55. Most people go 55 mph.
Those roads don't give FSD the chance to keep speed higher than limit more than 2-5 minutes because there are stops.
I have not tried auto speed on long roads that have no stop sign.