I will ad this for Tubman for information purposes.
It should be on it's own thread, not a faucet thread.
Fountain of Youth Bathrooms is a large manufacturer of walk in safety tubs and portable saunas.
Walk in tubs and saunas
The ones I have worked with have basically been "portable" tubs, even if they were eventually built in. The drain and water connections to them were VERY proprietary, usually hoses for water AND drain,and required some real ingenuity to connect them solidly to the house plumbing. One had a door leak and it could NEVER be sealed so the tub had to be replaced. You don't even want to consider the shower unit that had to have an access hole in the ceiling so the tech could get down behind it and make the hose connections. Then had to drag his ladder all the way through the attic to the garage, and finally slid the shower into place, OVER a floor drain, because there was no way to make a solid connection.