yo! Congrats on the jump to mirrorless! I made the exact same move from the D750 and honestly, the eye-af is literally magic compared to the old 51-point system. For your situation, I would suggest taking it slow with the upgrades cuz it gets expensive fast, but here's my take on the essentials. > Is it worth shelling out for a high-end ProGrade or SanDisk card right away, or can I get by with a fast UHS-II SD card for a while? Sooo, I think it depends on how you shoot. If ur just doing single shots or short bursts, a high-end SD card like the Sony TOUGH-G series SDXC UHS-II 128GB is actually plenty. It's rugged and fast enough for most things. But, if you ever do burst shooting, the Lexar Professional CFexpress Type B Silver Series 256GB is a better value than the super high-end cards mentioned before. It clears the buffer so much faster than SD, ngl. For the ergonomics, I definitely felt that "missing pinky" thing too. I compared two options:
1. SmallRig L-Bracket for Nikon Z6II/Z7II 2258: This is what I use. It adds just enough height for a full grip and makes tripod work way easier. It makes the camera a bit bulkier tho.
2. SmallRig Baseplate for Nikon Z6II/Z7II 2923: This is way more low-profile if you just want the grip extension without the side bracket getting in the way of the flip screen. Also, for power, I know the Anker was suggested, but I use the Baseus Adaman Power Bank 65W 20000mAh and it works great for charging the Nikon EN-EL15c Rechargeable Li-ion Battery while I'm hiking. Just make sure ur using a USB-C to USB-C cable for the PD charging to actually kick in... anyway, hope that helps! gl!

> Is it worth shelling out for a high-end card right away? Respectfully, I'd consider another option. Option A: CFexpress is fast but $$$ ($100+). Option B: SanDisk 128GB Extreme PRO SDXC UHS-I is $25 and works great for stills. Option B is definitely the move to save cash! Also, grab the SmallRig L-Bracket for Nikon Z5/Z6/Z7/Z6II/Z7II for like $30. It gives your pinky a spot to rest and it's way cheaper than official grips lol.

sooo i made the exact same move from the D750 last year and ngl, it's a bit of a shock to the system at first. honestly, i would suggest being really careful with the storage situation. while you *can* get by with a fast SD, it's basically a choice between the SanDisk 128GB Extreme PRO SDXC UHS-II Memory Card or a CFexpress. the SD is fine for hobby stuff, but the ProGrade Digital 128GB CFexpress Type B Gold Memory Card is way more rugged and clears the buffer instantly. i've had SD cards crack before, so for me, the extra cost for CFexpress is highkey worth the reliability, you know? also, definitely get a dedicated reader like the SanDisk Professional PRO-READER CFexpress Type B. plugging the camera into the laptop is fine in a pinch, but i've seen too many people trip over the cord and yank their camera off the desk... just dont risk it. plus, those ports can wear out over time. on the power side, those old batteries work but they wont charge in-camera. i'd grab a couple of the Nikon EN-EL15c Rechargeable Li-ion Battery for the best performance. for a power bank, make sure it has PD (Power Delivery) or it wont work. the Anker 737 Power Bank (PowerCore 24K) has been super safe and reliable for me on long shoots. lastly, the pinky dangle is real lol. the SmallRig L-Bracket for Nikon Z 6II 2258 fixed the ergonomics for me perfectly. it basically makes it feel as solid as your old DSLR. anyway, hope that helps! peace.

Been using this for years, no complaints