Just throwing it out there but why not go DDR4? Your motherboard and CPU might be slightly older but I've literally used the same mobo for like 10 years. Currently I have a Ryzen 5800x, Radeon 9070xt, 32gb ddr4. I upgraded the CPU in 2020 and the GPU this spring, selling my 6700xt to make up some of the hurt from GPU prices.

I can play cyberpunk on like max settings. The rig works great on Linux. I don't know how much of a difference DDR5 really makes since I've never had it but I feel like it's getting into diminishing returns for PC gaming, it can't really be noticeable that frames load 5-10% faster or whatnot.

On top of that, the 5800x3D is still regularly recommended despite being 4 years old. For arc raiders and older titles, some slightly older hardware could do wonders for you. I'd probably go this route than dropping $2k on a pre-built unless you really want Nvidia for some reason.

I'm very pleased with the specs I listed, like I said I can play the newest titles on max settings. You can prob build it for somewhere around $1k, mostly due to GPU prices. And if you build it yourself you get a better power supply, cabling, case, etc.