Maybe that's it the card has 10g mem, and the asset loads a little over 7G of bit maps and other stuff, then a ton of other shit also that I really don't know what is.. I have 25 G of shared mem to the 3080, which reports back as having 35G of total mem. I would think that would be plenty..... That asset is a pure HOG!!
Iray will not use shared memory in a GPU render, if you exceed the VRAM you're going to use the CPU.
The real issue is why are you loading so much into the scene? Most of it probably isn't visible and much of what is visible probably isn't required to complete your render(s). I've used Harwood house in quite a few renders and never come anywhere near filling up my 11gb of VRAM. Think of your render as a school theater set, put in just enough in just the right places and you can make a complex looking scene with very few objects. It's tempting to "build" or furnish an entire house and then just move the camera around but that's probably the worst thing you can do when rendering, the render engine isn't setup to work like that.
If you build your scenes starting from empty space and only adding what you need it's much easier than doing it the other way around. This will also usually result in drastically reduced render times and renders that need far fewer iterations to reach the quality you're looking for.
If you still struggle to keep the memory usage down consider playing around with "Scene Optimizer" (should be available here in asset releases) to quickly reduce the resolution on distant surfaces and even completely remove maps you don't need on many objects such as normal and bump maps surfaces that are small, distant or obscured by DoF or shadows.
Hope that helps