The guys with the skills and tools to pull this off are rare. I wouldn't hire anyone less than $80.00psf; the stuff costs us $25.00psf.

$80 would be rock bottom. Not sure I‘d trust anyone who charged the same amount as a counter top. This is much harder than you think. The material has to actually be able to travel through the house and through the bathroom door. Very often, that route isn’t large enough to have that happen, and walls must be taken down, and rebuilt, just to get it in the bathroom.

Now, the bath walls have to be super flat and plumb. That requires reframing all of lf them, or sistering all of them. Before the job is ever templated. You don’t get to cut a faucet hole in it after it’s installed. Your shower stub outs are fixed in place, and this has to fit precisely. Plus the stainless lugs in the studs that this has to mount to, etc.

$100 a square would be more the starting point. And only a very few folks in each region are going to really have the skill to start thinking about this.

I emphasize the points made above especially getting material into spaces. This also needs planning for proper support in space. It is not easy at all!!