Well, after a lot of talking with experts, talking with not-so-expert but opinionated acquaintances, lots of reading and watching reviews and opinions, collating my own comparisons from published product specifications and feature lists, handling lots of different cameras and lenses, I finally came to a decision. And my decision is not what I expected when I first started this journey.
I started out with looking at mid-level DSLR cameras, initially the Nikon D7500 and Canon EOS 80D. The D7500 looked like the winner. But then the Canon EOS 90D came into the mix and in typical technology fashion leap-frogged the slightly older Nikon product. The 90D looked the goods. But then that pointed me at the Canon M6 Mk II which has the same basic guts as the 90D, but mirrorless. So then I started looking at mirrorless options and that opened a whole new set of options and comparisons.
And in my case I do not have a cupboard/draw/shelf full of investment in legacy items like lenses of a specific type that would see me locked into a specific manufacturer or technology type. So all options were on the table.
So in the end, I agreed with many of the "experts" that mirrorless is the future and DSLR has a limited future in the world in which I am going to be participating (in my photography). So I fairly quickly narrowed the main contenders to Canon EOS M6 Mk II, EOS R, EOS RP, and Sony A6500/6600 or A7 Mk III. The cost step to full-frame models (EOS R/RP and A7 III) seemed justified for the capability enhancement.
If just interested in stills, the EOS RP would likely have been the winner (size, weight, price, capability), but it' video capability is somewhat nobbled (cropped 4K, limited FHD that is lens dependent). The EOS R is more expensive, but missing some of the features/capabilities of the newer, smaller, entry level RP so not great value in the current point in the cycle - perhaps a Mk II will see it leap-frog back to where Canon would like it to be positioned, but when?. The A6600 is pretty much a paper camera right now with nothing shipping locally (pre-orders only). So I looked more into the A7 Mk III and it has come up trumps for me.
Initial purchase is Sony A7 III, with 50mm F1.2 and 24-70mm F4 Zeiss lens. Add a couple of memory cards (SanDisk Extreme 128GB (UHS-I) and Lexar Professional 256GB UHS-II (1667x), and a second Sony battery, carry bag and tripod. Then later will look at adding a 70-200mm F4 G lens or 70-300mm F4.5-5.6G Lens and maybe a something like a 16-35mm F4 Zeiss lens (both about $1500 each, so will not be in a hurry).
Yes, the A7 III has some limitations/compromises, but for the price it packs a lot of features and superior performance to most others in its size/price bracket.