My X-Pro3 sub-monitor issue

Background

I’ve enjoyed my X-Pro3 camera since the first day I’ve had it. I previously owned an X-Pro2 which had been my sort of perfect camera, from street photography to travel photography. After long thought I decided to upgrade to the X-Pro3 and sell the X-Pro2 which I quite frankly regret sometimes, not because I’m not happy with the new one, but because I think the two can coexist perfectly as they have a different sensor and produce different images in terms of quality and style. Anyway, that’s another story, let’s get to the point :