I don’t own one myself but I have retouched a few jobs shot on one, the files hold up better than the MK II which was the last canon I owned but I think the Sony is a better sensor (I shoot on a Cambo Actus with a 7rIII) a friend of mine is a car photographer who sold all his Hblad gear (pre Sony sensor) and now shoots on a 5R in the studio where it shines as you can light to not give massive pushes to the file and you can’t tell the difference between those shot on the 5R and Hblad. He also shoots on a 1dx (II?) climbing/action images for a well known 3 stripe outdoor brand and finds the files too small but the R not able to handle the pushing the file and iso so is contemplating a switch to Sony, it’s not like the old 5s with the tartan shadow pattern when pushing but there is still a significant difference.
If you like the handling of the canon and are used to working with the files then you will get on fine. Re the C/A etc? Not really an issue but you need good lenses and you may start to see diffraction come in to play a bit earlier but if you take an R file and downsample to a 5d III size it will still be a better file even if the sensor out resolves the lens.
They are quite cheap now? Maybe see if you can pick up a second hand one to try?
The other option would be a 7rIII and a sigma adapter (not metabones) I kept a 24-70 2.8L, 24 and 90 TS-E when I moved to Sony and they all work well nicely together though I mostly use the Cambo with Schneider lenses as they are a step up in quality over anything Canon make.
This is all from somebody who has to hand over files knowing they are 100% usable. Somebody who prints (inkjet) or just looks on a screen will probably have a different view.
