Canon camera is always greater than the sum of its part and I consider the handling, ergonomic, usability such as high resolution EVF and control ring adapter. But this isn't the only metric I consider when buying a camera or consider a system. Sony 7AIII is going to be $1800 while Canon EOS R is $2300.
Panasonic has the ergonomic, better build quality than Canon, better EVF, IBIS, dual card slot, high resolution mode. I'm primarily a still only photographer. The AF has been improved. If you are primarily a still shooter, the AF isn't a huge issue for you. They recently update version to version 0.6 FW and the AF has been improved for a pre production model 2 months out. If you only shoot still like I do, I would consider Panasonic for its still features - eyeAF, animal tracking, Dual IS, DFD for no banding and striping issues, 1/320 flash sync speed, high resolution EVF and ergonomic, fully touch screen LCD, dual card slot, 30 fps 6k photomode, in camera focus stacking and high resolution mode. They look like to have a better sensor than 5D IV too and have good color science. Jury is still out for dynamic range.
Some of the high ISO shot look better than Sony and Nikon too.
Panasonic build quality is very good and provide weather sealing. I don't hold Canon to be the gold standard when it come to build quality. My 24-70 II ring rubber fall out, my friend 85 1.2 rubber started peeling off and so is his 5D III rubber. He doesn't even shoot professionally.
I have come to a sad realization that Canon may not be a camera for me. As a Canon only shooter for a very long time who has never switch, I think it's time for me to look elsewhere. They will always hold back specs to protect their DSLR lines or Cinema EOS line. I'm not consider Sony A7III but A7SIII/A9II. They will surely include their 5.8 million EVF. I can deal with ergonomic issue by adding an L bracket.