Sooo, for those 400Mbps bitrates, you REALLY need V60 or V90 cards!

• Sony SF-G Series Tough UHS-II SDXC 128GB V90 - literally the fastest!
• Stick to Panasonic DMW-BLF19 Rechargeable Lithium-Ion Battery Pack cuz off-brands can swell up... scary right?
• Get a Rode VideoMic Pro+ On-Camera Shotgun Microphone for decent sound.

V90 ensures no dropped frames during high-res recording. GH5 is just AMAZING!! gl!

Just sharing my experience: I went through this exact same struggle when I first got my GH5 a few years back! Honestly, I was sooo stressed about the price of those top-tier V90 cards... like, they cost as much as a lens sometimes, right?? Since I was on a super tight budget, I had to find some workarounds that actually worked for 4K without breaking the bank.

Here is what I ended up using:
* Lexar Professional 1667x 128GB SDXC UHS-II Card - These are usually around $35-$40 and honestly, they handled the 400Mbps bitrates totally fine for me.
* Wasabi Power Battery (2-Pack) and Dual USB Charger for Panasonic DMW-BLF19 - I know people worry about third-party, but these $25 packs were a lifesaver when I couldnt afford $60 per OEM battery.
* SmallRig GH5 Cage 2049 - I found a used one for $30 and it basically transformed how I used the camera for run-and-gun.

It took me some time to realize you dont always need the most expensive gear to get amazing results!! Anyway, hope that helps a bit. Peace!

In my experience, you should definitely grab some high-speed cards from SanDisk. Honestly, the GH5 bitrates are no joke, so you need the fast stuff. I've always stuck with Panasonic batteries too cuz generic ones can be super unreliable... trust me on that one lol. Also, definitely look into a variable ND filter from a brand like Tiffen. It's basically ESSENTIAL for run-and-gun stuff outdoors! gl!

Noted!