According to the youtube comments:
Question: "How to reset display back to standar setting"
Answer: "There are no default settings and also no wrong values as the display dont care about wheel size, magnets or battery voltage as long as it is between 24v and 60v"
On S866 LCD display pannel of my Sheng milo Mx20plus, I surprised that long pressing key"-" when set P16 , It can change all P's setting back to manufacturer's. (I don't know why not shown on their user manual)
Try it