Yes, you can, and there are commercial video wall products that do exactly that.
In my case, each screen will be driven by 1 gpu, same as it is right now.
Actually, that’s how the 4 gpus are working in my box. Each one only handles the data fed to it. So 2 x Arc 770 w. 16 gb ram is 1/3 more than an nvidia 4090, 1/3 more bandwidth total.
If I were stupid enough to pay crypto miner prices for a 4090, that 24 gb of ram would be divided among 2 screens, so 12 gb of ram per screen, instead of 16. Ditto data bus width aloocation - 384 bits allocated among 2 screens is 192 bits per screen, each Arc has 33% more data bus width per screen.
To the gpus, it’s just data. It all comes from the same cpu, and the cpu has no problem dividing the data flow between 2 screens on 2 gpus - otherwise my current setup wouldn’t work using 2 gpus to drive 2 screens in an 8192x2160 stretched center screen.
And if I find that I’m then cpu constrained, I’ll just throw in an i9-13400k. But I think I’ll be okay with last summer’s cpu.
The idea that you need to run just 1 gpu - anyone running 4 screens is doing more than 1 gpu, or they’re limited in terms of ram and data bus width per screen by their single card.