As an anecdote, I have a Sony a7r and operating it via its mobile app is one of the worst user experiences I have had in a while.
Same goes to the surrounding ecosystem of software. E.g. Adobe's Lightroom is full of obsolete paradigms and weird usability choises.
Usability of the camera hardware and software ecosystem is another matter. I think the common wisdom is that most paying users don't want beginner-friendly, they want powerful and familiar. So everything emulates the paradigms of what came before. DSLRs try to provide an interface that would be familiar to someone used to a 50 year old SLR camera, and Lightroom tries to emulate a physical darkroom. Being somewhat hostile to the uninitiated might even be seen as a feature.
There's also Sigma BF if that's what you want; Sigma actually do pretty good job from perspective of minimalistic, idealistic, on-point, field usable UI, though the return of that effort just isn't worthwhile. I have the OG DP1, it feels natural as IntelliMouse PS/2. I've tried dp2 Quattro once and it felt natural as any serious right-handed trackballs. They scratch so many of camera nerds' itching points.
Most people just buys an A7M4 and an 24-70 Zeiss. And then they stupidly leave it all to auto and never touches the dials. And it puts smiles on people's faces 80% of times. And that's okay. No?