No waiting required "if" Canon already has this coming. They could release the flip-TCs that work with EF now and not later – that would sell R bodies. Waiting for RF big whites is what's going to take patience.I don't see it happening, so I wouldn't hold my breath on that one.
Canon is more likely to want to push these high end buyers into including a new R5 in their purchase order.
We'll have to wait and see.. In my opinion, if that's what you're waiting on, you better have a lot of patience and tolerance for frustration.