Windows' fix is to entirely shut off the second CCD when gaming. So you will never see a performance gain from the dual CCD chips as long as it does that. Linux largely does the same thing, but I don't think they turn it entirely off. And those dual CCD CPUs need so much memory bandwith that even dual channel DDR5 chokes them out, it's almost offensive to the CPU to do that to it. And with that low end of a GPU I doubt a 9800 would be slowing you down. I have a 4090 and my 9800x3d almost never goes above 50% utilization. Streaming has a minimal impact on the CPU thanks to the GPU en/decoders. And if you use GPU encoding when rendering video then the CPU isn't that busy.
If you're gonna upgrade parts in the future why not get the MUCH better performance now of a 9800 with dual channel, then in the future upgrade the CPU? I doubt next gen will be a new CPU socket, and AMD has been great with that compatibility. Plus the rumors are next gen AMD CPUs will have 12 cores per CCD so you get the best of both worlds. Buying a 9950x3d and then pairing it with an RX 9060 is like buying a ferrari, and putting donuts on all 4 wheels. Yes hypothetically in 10 years of driving 1000 hp might come in handy. But 9.999 of those 10 years you're missing out on so much. If the 9800 can't run the game in 10 years then the 9950 won't either.
A much more sane setup. You'll still be very GPU bottlenecked, but much closer in terms of pairing. I prefer a CPU over a GPU bottleneck anyways since multi tasking will bring that down. But I doubt you'll ever see much of a CPU bottleneck with the 9070. And since you have 32 gigs of ram you're not going to be horribly RAM starved. Full fat linux distros aint the light thing they once were. Catchy OS on startup uses like 3.5 gigs of ram, and running FH6 I was using just under 16 gigs of ram not including what the iGPU was reserving. And that was on my old laptop. Nowhere near as powerful as that.
You could save a few bucks by getting a pcie gen 4 SSD, and maybe spring for a lower end 2TB drive with the money saved. The speed difference isn't that insane like sata to NVMe, or even gen 3 to 4. But that's personal preference, and x870 has plenty of spare PCIe lanes for getting a second drive later on.
Also since your case has a PSU dungeon you don't need to pay the white tax for a white PSU. With a modular PSU you can replace the cables with custom aftermarket ones, but you might be paying more than the white PSU for those. I'm not fully up to stuff on PSU quality tiers, but as long as that's a highly rated one 850 watts should be plenty. That one seems OK, but gigabyte has had really bad responses to exploding PSUs so I'd maybe stay away. If you go by this list then shoot for B tier at minimum. A good white PSU will cost money, but you do have the dungeon.