Yes, they're "just" pcie, though units like H100 and newer (or did it start with pascal? i really don't know) have variants that use a proprietary connector called SXM, but it's always just pcie lanes underneath. In some versions there are interposer and mezzanine boards, but again, pcie with associated bits and bobs like retimers and pcie switches. Not impossible to integrate, just annoying.

So, sort of specialized? but not really.

> If there's a will, there's usually a way.

That's the spirit!