Yep, I doubt there'll be a 6D MKIII. Having said that, I love my 6d MKII but recently got the EOS R and since have used that 95% of the time - a bit smaller & lighter with a better sensor, although for action shots I'd probably still use the 6DMKII as first preference. I think they make a good pair together though...I think you're going to be waiting a while. The 6D II came out in 2017, and with the past 4 year release cycle you'd be looking at summer 2021. That's assuming that they ever release a new 6D series camera. The RP might be a suitable alternative in all honesty - it's not exactly the same, but it's close.