About the R1: First, remember this is a unicorn at this point. No one knows when and if it will materialize.
Everything about the R5 and the 1DxIII says to me that Canon is in no hurry to release a 1 series mirrorless. Is there even a market for one?
Once again I link to this article:
https://www.canon-europe.com/pro/stories/future-of-dslrs/
If the R5 is as good as promised, it will suffice for quite some time for those who want to shoot action with a mirrorless. I suspect Canon did not hold back on the R5 but instead pushed it to the limits of currently available mirrorless technology. We will have to wait until it is released and we start seeing reviews, but if it comes close to what has been promised, it could leave very little for an R1 to offer.
Expect the 5DV in 2021 and the R1 in 2022. Canon could put the 1Dx on a four-year summer Olympics cycle and the R1 on a four-year winter Olympics cycle.