I used to work for floor restorers. All hard floors are inherently slippery, especially when wet. But a texture increases the friction co-efficient, thus making the floor less slippery. But of course the texture (imagine sandpaper) means that there are lots of crevices for dirt and grease to hide in, thus making them a PITA to clean, especially since that grease and dirt attracts more of the same. Here’s how the professionals deep clean waterproof floors, things like stone and Altro (which is the slightly sparkly non slip stuff you often find in public loos). Mix up your preferred cleaning solution (I’d use one with good anti grease properties here) and test in an inconspicuous area in case it damages the floor. Protect adjacent floors with old towels or whatever, because you are going to puddle the solution on the floor - imagine a washing machine or dishwasher flood, but a bit less dramatic! It may be easier to dam the floor in sections to do this. Let the solution dwell a little while, and agitate it with a brush/broom. Let it dwell a bit more, and agitate again. Then remove the now dirty solution, a wet and dry vacuum is good for this, but you can mop it up. Now the floor is actually clean, regular wiping/mopping/steam cleaning should be more effective, but you’ll need to repeat the deep clean periodically.