Here is an interesting patent application showcasing what appears to be new design and functionality of an integrated grip mirrorless camera body. At this time, there's no way to really know if this design is in fact one Canon is moving forward with on a camera body such as an EOS R1, or if it's just part of the design process.
Japan Patent JP,2021-117300,A mostly deals with a secure grip for both horizontal and vertical shooting.
This design is quite unique in that there is an open cavity in the body that your fingers can grip through as you can see in the patent illustration below.
This is definitely some out-of-the-box thinking when it comes to camera design, but I think the open space within the camera body is a lot of lost real estate for electronics. If you've ever seen a camera opened up, there is rarely enough space inside for much of anything.
One of the applications of the pass-through design is for active cooling, which is something we will see in the future on the Canon EOS R5c, but I can't see the EOS R5c having a fully integrated grip, as it has been described to me as “slightly larger than the EOS R5”, but this design would fit as significantly larger.
The patent also mentions touch bar functionality, which wasn't well-received on the original Canon EOS R.
Could we see some of this design in the EOS R1? Perhaps, but it seems a bit too radical in my opinion.