Ah, but: in that image you are working at what appears to be a well stopped-down aperture which hides a multitude of focussing mistakes.
I have been tending to work either wide open or about a stop down at best; not that it's any better a way or not, just that I need to differentiate planes for what I'm trying to achieve these days. So due to that, which as you know means pretty much WYS(on the screen)IWYG because af on a dslr works at wide open - as does manual focussing unless you want to stop down to the working aperture just to check - which on tiny cameras screens ain't that brilliant either (no, not going to cry over the number 500 right now!), I found that using manual in those situations was often the best way open to me (not counting the eye probems that have hit me). However, a glitch still remains because a 50mm at f2 or f1.8 on 135 format cameras, used at the distance it has to be in order to cover an area of what - six feet-wide window fame? is going to have too much DOF for my intention, especially when the reflected plane I want crisp is of something perhaps a few feet behind me... I need a super-fast which I ain't got!
I wonder how a rangefinder mechanism works out what you want (in the case of both our intentions with these sorts of confused images); at best, I'd imagine it to have exactly the same decisions to make as any other system, with the same problem of knowing what's key.
But as I've indicated before, the last time I touched a Leica rangefinder camera was '65 when my last boss had one (and the only other Leica I've held was an R6 many years later), and so I'm not at all qualified to comment on how a current Leica M might handle in reality.