i'm still enjoying the Z7, although it's limitations relative to the D850 are definitely becoming clearer, and they primarily have to do with focus. i'd say most of my shots with the f/1.8 primes of moving subjects are out of focus. this (and EVFs) has always been my issue with mirrorless cameras, and i don't think nikon has solved it. still a fabulous camera for many many uses.
focus peaking at larger apertures seems unreliable, and in particular there is something about using the z7 + ftz + 19mm pc-e which is very awkward and easy to screw up. you don't want to hold the thing only by the camera, but since the lens shifts there isn't a great place to grab the FTZ, and most of the rest of the smooth part of the lens is focus ring. obviously this lens is often used on a tripod, but i have often used it handheld on the d850 with absolutely stellar results. i was hopeful that the evf of the Z7 would make it easier to use still, since you wouldn't have to look at the rear LCD to focus it. sadly not, it's just ergonomically very awkward.