I don't think anything can buffer 30 FPS unlimited yet.
Z8 I can at 20 with HE. And how I don't overflow the card is I shoot until the thing happens, then stop, back LCD scroll and protect the few poses I want, immediately in playback delete all. It just keeps the protected. I repeat this. NO card space issues. When I get home I don't have a zillion photo's to sort though. With how fast you can scroll though them, like fast forwarding a video it's pretty efficient. I just do this as I'm waiting for more things to happen. There's even a key on the back dedicated for it. All I need to know is the composition positions right, posed right quick check on focus if I'm concerned and that gets protected for review at home. I don't even pop cards out of cameras anymore, just wireless transfer.
That's my workaround to not having Pre-Capture RAW and it's not been that big of a deal. There's a lot of waiting for wildlife to do things. If it was hectic that's what a spare card's for. HE does not use much space. It's about 18-20000 shots on a 512 GB card. That's about 15 minutes of strait shooting at 20 FPS.
They're still 14 bit RAW files and I cannot tell the difference in practical use between lossless compressed, HE* and HE.
Now would I want pre-capture to include RAW, of course who wouldn't, it's still more efficient. But a Z9ii with pre-capture offers nothing I don't already have for ability to capture a shot. It ends up being a really expensive convenience feature.
Now what else they may come up with, in addition to that may sway me if they make enough advancements. But Pre-capture RAW and 10 FPS will not be a sale for Nikon for me personally as I just won't capture much more than I already can.
That's just me, for some it's enough to spend the money.
I'd honestly be more impressed if we can pull NEF from the 8.3K 60 at 38 megapixels in camera.