It looks like the resolution of the sensor in the Canon EOS R3 has been confirmed at 24mp. It looks like EXIF data that made it out of Tokyo Olympics images have made their way to the Canon Rumors Forum.
The EXIF data shows an image size of 6000×4000 pixels, which puts us at 24mp.
Canon EOS R3 Specifications:
24mp backside illuminated image sensor
Multi-Controller & Smart Controller
Vari-Angle Touch Screen
NEW accessory shoe
High speed 30fps electronic shutter with AF/AE tracking + RAW shooting at this speed
AF down to -7.0 EV...