Thanks for all the useful tips and advice, guys. In the end I decided to buy the R6, and a second lens with the difference in price to the R5. So got myself the RF24-70/2.8L and the RF14-35/4L. What I think tipped the scales finally towards the R6 was the fact that I needed to fork out for that highspeed CF express card to be able to have a backup card, even though I shoot very little video.
I will carry on with the upscaling feature in CR for now, if needed, and consider buying GigaPixel if if I have to.
