My partner who works from home has a NDA which means nobody is allowed to even be in the same room while she is working.

That room is more than wanted...

I've got two monitors and a laptop on 1/3 of my computer desk. I'm huddled on a corner literally the point is right where I work. My mouse is 10cm from the desk edge. It sure feels like I need extra room.

You need a bigger desk not a bigger room. Make some compromises and remove some other furniture in the room to accommodate your bigger desk.

Bigger desk doesn't fit if the room is too small. I literally need more room the room itself.

You mean like a desk, a chair, two monitors, a camera, microphone, and video light? That type of special equipment?