[wim]

The UI question is not so easy. The EOS R is a good example. As mentioned some time back, it's terrible to use out of the box - FOR ME. Following some customizations, it worked greate - FOR ME.
I never had issues with Fujis but then your mileage may vary. Conversely, I never warmed up with Nikon DSLRs.

Why?

It was very easy to me. Switched to Av and off I went. Thereafter I just tweaked features and buttons to my liking, once I got to know the machine a little better.

I see a lot of comments on the interweb on this supposed lack in the UI, basically from users of dslrs who want to immediately shoot with their preferred settings they have been using for years. Obviously that does not work, because you have to transfer those settings first, and partly translate, but the EOS R is very configurable. In addition there are so many AF points that one can’t expect to work these with a joy-stick type device, and the option to either use the screen for manoeuvering these AF points or the control pad is iMO an excellent solution, and works well indeed.

To control exposure and actual shooting, there always is the Q-type menu that is reachable from the Info button, so control of parameters is very easy from that PoV.

I think remarks on usability or the UI are in a way similar to the remarks on the Olympus menu system. IMO it is not complicated at all, it just is very complete, and therefore possibly more difficult to find specific items. Simply shooting straight out of the box is always possible, and easy, there also is a Q-menu, and the whole thing is completely configurable to one’s liking, just that that takes a little time.

Basically, I got the camera, played with it for a few hours, shooting some macros of flowers, and some test shots, just to see how some of it worked, and thereafter shot a wedding, in circumstances from rain to sunshine and at night, very dark with a fire dance, with a variety of EF and RF lenses, no flash used, with absolutely no problems.

AFAIAC, the UI is very good, just that one needs some time to optimize it for one’s own use.

Kind regards, Wim