Remove and replace shower river rock tile flooring and marble wall tile water damage help - Tile Advice

[nose1182]

This is my first time posting, I searched for a similar thread and didn't find much- apologies if this is a repeat!

My upstairs bathroom has a walk-in shower with marble wall tile and river stone floor. The river rock flooring is getting messed up. The grout is cracking and coming loose, and a few single stones have popped out on their own. I would love to remove this tile and replace with something that is easier to maintain with less grout to clean.
Can I just take a hammer drill and drill it out? Chisel it out? Then lay new tile?
I know that river rock tile has been an issue for many folks, so I hope someone else can share their experiences to help. 🙏

Another issue is the marble wall tile is "taking on" some water on the row touching the floor. There is a water line on some. I can stand directly under part of the shower and there is drywall without any signs of water damage. Just on the other side of part of the shower is my closet. I removed a small piece of drywall to get a peek. There is a gray rubbery membrane that goes up about 12" from the floor, and the back of some type of material. No mold from what I can tell 🤞.. Does it look like it was waterproofed done correctly? Is it ok for the tile to be soaking up that much water? (The shower has not been used in 2 months). I'm nervous about a water leak and any potential of mold/water damage to my home.

 

[Tile Marble Granite]

Looks like an Oatey shower? Send more pictures if possible. How old is the shower?
These showers are built with a shower pan liner ''rubber membrane'' that is what you are seeing 12'' up the wall.
The water penetrates the grout, mortar bed is soaking wet 24/7. Did you check the pitch down?
River rock floors collect water by nature. Too much grout.
We can talk about these showers all day long.

 

[nose1182]

Thank you so much for the response! The shower was built 2011-ish. It seems like the way the "backer board" is inside the liner it would be getting wet. How do people prevent this?
I can definitely upload more photos, anything specific that would be helpful?
I have not measured pitch before, but gave it a shot and I think it is 1.75" for 25" length. (I attached a diagram of how I measured).

 

[Tile Marble Granite]

Send us some pictures during the work, that would be helpful.

The liner is installed before the drywall/backerboard, it is stapled 6'' to 12'' up the studs, no staples allowed lower than that. The drywall/backerboard is installed on top of the liner then the tile.

Measure the pitch from all 4 corners. It looks like a big custom size walk-in shower.
Grout speaking: if its cracked and loose that means there is a bounce in the floor.

It looks like the shower pan is installed on top of a box, is that 3'' high?

The wall looks like granite tile. It absorbs water from the floor