[KolenCh]

First sentence incorrect. £850 is not top end.

A typical high end camera product would starts at $2000, and nowadays more often than not is $3000+.

A quick search shows the top end of Fuji X mount is $2000+.

And that’s not even the top end of Fuji’s, which goes to the medium format GFX mount.

For your other points, I know you’re talking about app, but Fiji has been famous about their software support in terms of how long they continue to update their firmware. They even market it Kaizen. And it is an objective truth that you can verify by comparing to how often other brands upgrade their firmware (Sony is not bad but still not as good.)

There exists open source softwares on camera, just may be not Fuji (I don’t know.) If you want open source softwares running on camera which significantly increases its capability, try Canon’s. That one is the most mature.