I have been told a couple of times now that Canon is working on a new menu system for upcoming cameras. I don’t know how far along in development Canon is, but I would think the EOS R1 would be a good place to introduce something new.
One of the sources claims that you will be able to select the “Canon Classic” menu system or the new menu system on your camera. This makes a lot of sense, lots of people love familiarity, especially on professional bodies, but new users to the system would probably be inclined to learn the new menu system.
Canon has always had a great menu system, but I think it has started feeling cumbersome on the EOS R5, as the breadth and depth of options continue to grow.
Before you ask, I doubt we would see a firmware update to give cameras like the EOS R5 or EOS R6 the new menu system.