Yoga Chair for Adult,Yoga Lounge Chair Supports Up to 330lbs,loveseat for Relaxation, Ideal for Living Room, Bedroom or Outdoors

Could be your shower walls, but typically those are a flat, smooth, non porous material which is what you would want. If you have balance issues maybe try one of those stools like below? Might help with balance while trying the floor. https://www.amazon.com/dp/B0FG88QG59/ref=sspa_mw_detail_3?ie=UTF8&psc=1&sp_csd=d2lkZ2V0TmFtZT1zcF9waG9uZV9kZXRhaWw