I said this on Pnet, but I'll repeat it here:
I am a heavy Nikon DSLR user, and in fact have built up my Nikon DSLR kit over the past year as prices have fallen. Most recently that included a 300mm f/2.8 VR1(I've never had a 300mm f/2.8 and truthfully it will only be an occasional use lens for me, but it's also been an "I want it lens" for me even back in 2006 in high school/college when I was using Canon FD mount cameras exclusively and no plans to even move to AF, much less digital). My two main Nikon DSLRs now are the D850 for most of the time, supplemented with a D5 when I want speed, low light, and much to my surprise RAW files SOOC good enough that I could ALMOST shoot JPEG. The D5 effectively replaced a rarely used D3s, mostly because I have other cameras that have equal if not better high ISO performance, and a gripped D850 w/EN-EL18 has better AF performance all around and nearly as good of a frame rate. The D850 effectively replaced my still used somewhat often D810 as a natural upgrade/progression(the D810 had, in 2020, replaced my much loved and still owned and used D800, and even though I see similar IQ between the two I appreciate all the little touches that the D810 has like the nicer feeling grip and much quieter shutter). The only sort of odd one out I have with no replacement is the Df, which is only completely incompatible with 4 or 5 F mount lenses in the entire history of the mount(only one of which I own, and I don't really care about using it) plus offers low light nearly as good as the D5, a little better than the D3s, and in the lightest FX DSLR Nikon has made.
With that rambling introduction, I'll also mention that as my F mount collection has grown in breadth, many of the individual pieces I use regularly have also grown. I have a full set of f/2.8 zooms covering 14-200mm, but my only current one is the 24-70 f/2.8E. It was an ugprade from my older 24-70 f/2.8G in most ways(I love having VR even on an f/2.8 lens, and splitting hairs but these high resolution bodies appreciate the optical improvements) but it's nearly as big and heavy as my 70-200 f/2.8 VR1.
I have a 5 month old son, a first child for my wife and I both. Needless to say I have her blessing to carry a camera almost everywhere, but my usual grab and go D850+24-70 is...well...a lot. A late May vacation had me start seriously researching mirrorless options, and in particular I focused on APS-C offerings since with purpose-built APS-C lenses there's a nearly automatic size advantage, and also often an optical advantage from needing a smaller image circle.
I first looked at the Z50 and ZFc. I liked the feel of the ZFc and how it feels a lot like a Df successor that really does a better job of actually pulling off the whole digital FE2/FM2 concept. Still, though, aside from it being hard to hide that it's based on a low end body(Z50) the real turn off for me is that Nikon seems to be continuing their tradition of not really building a great DX lens selection. Nikon more or less exited film in 2006 when they killed off everything but the Cosina-made FM10 and the wonderful but expensive F6(yes I have one and love it, but the F100 is 90% the camera at a much lower price new and used). For the most part, though, even before the mass purge of film cameras most of the focus and probably sales for a few years prior had been crop sensor DSLRs, and that was the case until the 2008 D3(unless one branched out and bought F mount Kodaks where you could get APS-H and full frame). Still, though, most of the pro grade lenses introduced in the early 2000s were still full frame lenses. Some, like the 70-200 f/2.8 VR1, definitely favored center sharpness which benefits APS-C cameras, but there still were a lot of great new full frame lenses in that period. As full frame moved to a bigger and bigger chunk of Nikon's sales, there were still some new DX lenses like the excellent 35mm f/1.8, but a lot were plasticy consumer(even if optically decent) lenses like the 10-20mm f/3.3-5.6 AF-P.
Unfortunately, I saw the same in Z mount. Yes, I could buy full frame Z mount lenses(which are now plentiful and tend to be very highly regarded) or even adapt my F mount lenses, but that just leaves me with big heavy lenses on the front of a small body, which kind of defeats the purpose.
So, Fuji started getting a serious look from me, not the least of which because I love physical controls and the mount is very mature with a great selection of lenses, all made for APS-C. After a lot of research, shopping, and looking at options I ended up at an X-T5 and 16-80mm f/4 kit. While I was researching, deciding, and debating Nikon did announce the 12-28 PZ lens, but it still wasn't quite enough to change my mind. The new 24mm came after I'd bought my Fuji and already put it to some serious use. Even though the price is attractive, the Fuji 23mm f/2 still strikes me as an all around better lens.
So, instead, even though I will still be using my Nikon DSLRs for the forseeable future, the X-T5 isn't going anywhere for me. My next purchases for it are likely going to be the 23/35/50 f/2 prime set(maybe one at a time, maybe all together) and a Fringer adapter since I just have too much great F mount glass to not use it even though my preference is still for native lenses. We'll see where I go with Fuji in the future. I have to admit that it was a few weeks of initial frustration(despite reading and watching most of what I could find on the camera, plus frequent trips to Google to find specific things) and the camera still catches me in moments of "Why are you doing that?" or "Why does it work this way?" but as I've learned my way around it I have learned to work with it and figured out what control layout works for me that's gotten a lot better.