Mark, I really don't understand problem with EOS. Every EOS camera can be set to manual expoxure, lenses can be set on manual focus mode, and you have all manual camera. You don't have to use complicated interfaces if you don't want. Buy split focus screen for your EOS, set camera and lenses on manual modes, and problem is solved...

I have EOS 3, and I use it on all manual mode or aperture priority mode. My EF lenses are allways set on manual focus mode. I wear eye glasses. So, you can do the same. Yes, I would love Leica or Zeiss lenses instead my Canon lenses, that is why I would like R6.2 or Aria, but that is because of lenses, not camera body. I can use my Canon body same way (manual) as any other manual camera if I want (Ok, except film winding )