Baking soda, hydrogen peroxide, and a bit of elbow grease: ) via a soft scrub brush.

You can’t have 1 cleaner for walls and outside the shower and 1 for the shower floors. That isn’t how people clean. Throw out everything but a pH neutral stone cleaner. Make sure your cleaner knows to never use anything with acids. No toilet bowl cleaners, mold removal cleaners, soap scum cleaners. None of that.

This goes for you throwing out all those soaps and skin care products that have acid in them to. Thats acne products, retinols, hyaluronic acid products, and many hair conditioning products.

Jan Moyer - you know your stuff!!!

IMO a new bathroom requires little scrubbing if after each shower you squeegee the walls of the shower and the glass door, The a neutral cleaner and a good rinse after use and I like to take a cloth and polish the walls and the floor . I agree with Jan as far as the products you use should not be near the marble. I use Mrs. Meyers in the concemntrate form to dilute for whatever job I need it for . I like the Lemon I find the Lavender too strong of a smell. So I use it full strength in the kichen for my hood and anyo other greasy think and usually cut 50/50 for the bathroom I use vinegar in the kitchen to make sure no soap residue remains after cleaning

Find one cleaner that is stone safe, and stock only that, and use only that. You will have to avoid many things with acid that will damage marble.