Canon EOS R5C Manual page 711

Customize dials
Frequently used functions can be assigned to the <
1.
Select [
2.
Select a camera control.
3.
Select a function to assign.
: Customize dials].
Press < > to set it.
You can configure advanced settings for functions labeled with
[ ] in the lower left of the screen by pressing the <
>/< >/<
711
>/< > dials.
> button.