Thank you all!
The comment that the jump from A7 III to IV is much more of consequence than the jump from IV to A1 is pretty entriguing, actually.
Although, viewfinder dynamic range plays a part, too.
I only tried the "good" viewfinder (9mpixels) on a Fuji gfx 100 II, and was actually... underwhelmed.
Do not know, I was expecting maybe too much.
But: what about operational speed?
I hate, really hate sluggish cameras. The dials on the A7 III have a perceptible delay, the menus, everything. Are newer cameras faster? A7 IV already? or has it to be V or A1?
Thank you again
PS
Tried a Z6 II with their 24-70 2.8 last year... came away very much unimpressed, so much so that I sold it after a couple of months. So no Nikons: that time has passed (I do long buying another 105DC, though...).
I hesitated only for the Fujis (I had budgeted for a GFX100s II + 32-64/4), as the image quality is just breathtaking. But the heft, and the very lazy operational speed drove me away.
Too bad, as I need to repeat myslef: IQ is astounding, imho.