Canon EOS R5 Mark II Advanced User's Manual page 583

Note
[ ] is used to start shooting without touching the camera (to avoid camera shake)
when it is mounted on a tripod for shots such as still lifes or long exposures, for
example.
After taking self-timer shots, playing back the image ( ) to check focus and
exposure is recommended.
When using the self-timer to shoot yourself, use focus lock ( ) on an object at the
same distance as where you will stand.
To cancel the self-timer after it starts, either tap the screen or press < >.
Auto power off time may be extended when the camera is set for remote control
shooting.
583