i reckon "a bit slidey" is good if it's stable enough to hold them when they're on it.
when they're a bit older, they'll want to move the step around to access stuff themselves, and if it's hard to move, you'll be called in all the time to move it for them.
I've got an ikea bekvam step that I'm turning into a toddler step stool.
The feet are a bit slidey on the kitchen floor tiles any suggestions to make the feet gripper?
They look like this