I still feel that the coming Z9 with your 500E lens is a vastly better proposition than the Canon R6 with the 500II, even if it takes half a year of patience. The R6 is ony 20mp, does not have a stacked sensor, does not have an integrated grip, and does not take your 500E.
Believe me, I have jumped around my own fair bit, e.g. not suffering 6 months of waiting for the 500PF when it was impossible to get. I have learned my lesson I guess, just stick with what you like and wait a bit longer, otherwise chances are that you will be changing back like I did a few times. I could easily buy a Nikon Z9 for all the money thát cost me I can tell you.