A brief recap on how I got to this point: My first venture into FF was with the classic and excellent Nikon D750. However I shot a lot of wildlife and paired the body with a Tamron 150-600mm. Did the job well enough but that isn't the greatest lens and it's heavy. The answer to the weight and quality was the truly splendid and light Nikon 300mm PF with a TC, but to keep some reach I also switched the body to a D810 for the greater pixel count (either more scope to crop, or just shoot in DX mode for a 1.5x increase in EFL).
Time marches on and inevitably the hands got a bit achy on the rheumatic side and reluctantly the D810 had to go for a Z - but which one? For me it came down to the Z7ii or Z6ii, and perhaps a bit surprisingly given the D750 to 810 story I opted for the Z6ii. There's quite a big price gap and I couldn't really see anything in what I was likely to shoot that justified it; add the better high ISO handling of the Z6ii and the choice was pretty clear for me so a new Z6ii with the "kit" 24-70mm lens along with a decent summer sale discount, and it was a no brainer. The word "kit" is in quotes because this is one of Nikon's S-series range of glass and has had rave (and justified) reviews for its quality.
I've had the rig a month now and nearing 1000 clicks in a variety of circumstances, some forced on me due to entertaining family visitors, but the rig has exceeded expectations. It takes the 300PF with 1.4TC and the FTZ2 like they were made for each other, and the 24-70 is now my go-to lens for anything that doesn't need the reach (the 70-200 zoom works just fine too, but the only time I've used it was to see how it went with the FTZ - see below). The body size, weight and shaping work perfectly for me - a wee bit of a pleasant surprise.
What next, if anything? I anticipated that there would be advantages in moving to Z glass and had traded most of my F-mount gear. I'm so impressed with the Z 'S' lens that I'm glad I did, even though there are some eye-watering price tags too ... Best guess is the 70-200 will be traded against a new 105mm 'S' macro, and the rest can wait until I've had a bit more experience in different situations (and there's more availability in the used market).
Bottom line - delighted and not a little surprised - with how things have gone.
Any downside? One niggle I need to spend time on and it's almost certainly the user not the equipement: the body has 3 'U' options where you can store the menu set up for different shots, in my case Action/Wildlife, Portrait, and Landscape. However it seems that to change exposure (I shoot M with Auto ISO mostly) you have to go out of the 'U' setting and back to 'M' - no big deal but certainly a niggle.