Canonrumors reports that Canon might announce a new 75 Megapixel EOS-R camera in late 2019. From what I heard (and CanonWatch heard the same) this seems to be unlikely to happen in 2019. Yes there will be a High Resolution camera but it’s going to have a lower resolution.
What we heard is that Canon is in heavy process evaluating the EOS-R hits and misses. While they nailed it with the RF lenses the camera lags seriously behind the competition and has some usability issues too. That is something Canon will work on before to launch a new EOS-R Pro Level camera.