Hi! Could anyone help me out with my problem, I'd like to make a carbon bath, but the most nesessery thing about this project is good looks without anything accept carbon and good enough grip so that it won't end badly. If you have any suggestions leave them here please!

I would make a test with sanding the carbon, then apply resin with a roller, and then use a salt shaker to uniformly disperse salt onto the surface. Once cured the salt washes out and only leaves the craters in the  resin behind.
It's a technique used on surfboards sometimes, but never tried it myself. Might be a nightmare to clean tho.