"Customer may not [...] provide commercial hosting services with the SOFTWARE. [...] The SOFTWARE is not licensed for datacenter deployment, except that blockchain processing in a datacenter is permitted."
So if you were e.g. an ad agency artist using a 4090 at your desk to generate images for commercial use - that's fine, because it's not in a datacenter, and the commercial services you're providing with it aren't hosting.
I've never heard of nvidia taking any enforcement action, or defining precisely when an office becomes a datacenter - I suspect this is mostly to ensure the big cloud providers don't offer 4090s.
Reading my comment again, obviously it wrong and I should have been more careful with the wording.
The worst thing that can happen is Nvidia declining any warranty repairs on these cards as they've been used outside of the intended use. But it's definitely not a legal issue.
And EULAs in general are just not enforceable outside of the US.