Do you already have a system or are looking to build a new one? If its new I'd say just go AMD if it's Linux you're running because half the Nvidia features you'd get on the card don't even work with their crappy blob drivers. Its probably gotten better since the last time i tried but its not a plug and play experience. I don't believe anyone who says it works fine I'm like the biggest linux advocate I've been using it for almost 2 decades but nothing on linux has ever been as simple as "it just works" especially for nvidia.

There are some decent value AMD cards on the market something like the 7800xt wins out over the 4070 at the same price point. You're also more likely to be able to use the full feature set of an AMD card on Linux and it will work without any issues on Wayland which is important as more and more distros are dropping xorg completely. Cheaper AMD cards in the 6000 series have very competitive price to performance

If you get an all AMD rig you can accces AMD Smart technologies that can do some synergies.

Big one being Smart Access Memory which allows the processor direct access to GPU memory.

Frame Generation -
I'm not too familair with NVIDA version of it but there are some games where the driver will automatically turn frame gen on and it works well...except it basically tells the card to go nuclear. Like I have a bougie 7900XTX and Hades 2 was giving temps of 105C on the gpu memeory 640fps

So I had to go into Adrenaline and tell the card to AMD Chill and limit frames to 120.

On the other hand Super Resolution has gotten really good. You can take a 1040 / 1440 res and do 4k res fairly easy now with minimal processing.

NVIDIA does ray tracing. AI, and cuda things better. AMD still capable of these things.

AMD has been on a tech spree lately and it's like getting free upgrades to the card.

Modern games 8GB won't do you. I recommend 16GB to give room for modern features and things that a normal desktop user would have in addition to the game reguardless what team you end up going for.

If all you want to do is game and have a Linux desktop, the Steam Deck OLED had a linux desktop with a dock accessory to display that on a tv or monitor. Cheaper than a full big box machine.

AMD. Had horrible problems with Nvidia drivers on a rolling release distro, haven't run AMD with one but it's been smooth sailing ever since I switched. Running a 5600xt, plays Death Stranding at 1080 pretty competently.

Yeah always go for AMD over nvidia on Linux. You will have way fewer issues in general. I bought a used AMD card off local facebook marketplace for not that much money. Take a look and see what’s around you then get the best card you can buy for your budget.

Should be noted because I’m a pedantic dickhead that while AMD drivers (the thing running on your CPU to let Linux talk to the GPU) are open source, their GPU firmware (the OS running the GPU computer inside your computer) is not. So if you want to be a hardcore “libre” Linux person there aren’t any real decent GPU options but it isn’t that big a deal imo.

AMD. Without knowing your budget, I would suggest a used 6800XT for great p/p.

What's your budget and how much grunt do your games demand? You might do OK with something in the RX 5000 or 6000 series. These might only be available as used/refurb, but if you shop carefully you can find good deals, and some refurb cards even come with warranties on ebay.

I just picked up a refurb 6750 XT which was a huge upgrade over my 1650S. It's running great in Bazzite, and since it's an older card but still meets my needs I feel like I got a great deal. Even better that it was a refurb. I'm very happy so far.

I am running an RTX 2060 just fine on Linux with really no issues. Wayland is iffy if you want to use that, though it's getting better

I bought the top of the line AMD card a few years back and never got the goddamned thing to be able to use both my monitors on linux, and on Windows the performance didn't seem all that great. I ended up taking it back after pulling my hair out for a day or two. I bought an nvidia card, plugged it in, it worked right off the bat in Linux and the performance was insanely better on windows. I never looked back.

Also if you care at all about running any AI apps then forget AMD. You'll really want a card capable of CUDA and that's only Nvidia as of now.

Do you actually have more than one cowboy game?

I have a laptop with a 4050 and it works great. Granted, I run everything other than games off my CPU so the only issue is HDMI.

If you want less of a headache, just go AMD. FSR may not be as good as DLSS but the extram RAM will help you a lot more in the long run.