Or just do what Sony did for the A7SIII and A1 and offer dual hybrid card slots. 1 side of each slot takes SD cards, the other side takes CF express type A.I used to think like that, but in actual fact my real world card use suits a fast card and a ubiquitous card type combination much better than two fast and expensive specialist cards. So I am happy with the choice.
I’m sure the R1 will get two same type high end card slots So save your money and anxiety for that release.
Canon could do the same and offer SD and CFX type B hybrid slots.