Eye-controlled AF point selection seems to work well for some people, but badly for others. I photograph insects in "awkward" positions and often have to contort my head at angles to the EVF, so I don't think eye-control AF would be of any value at all to me, as I imagine your eye has to remain in a constant position in relation to the EVF eyepiece, for it to be reliable.
I could find plenty of use for *hand-held* focus-stacking and various computational techniques that involve merging, but for the foreseeable future I think these will be confined to sensors smaller than FF. In the Canon world, I'd expect this to happen with the next "R7ii", but even then it would I think be quite limited in effectiveness, compared to M43.
Yes, GBP 2730 from Panamoz, but available slightly cheaper from untested sources in Switzerland, via eBay. I'd stick with Panamoz.