Long and short of it. My bathtub’s spring stopper has deteriorated. Building manager solution was to use a rubber stopper. I looked for a replacement part, couldn’t find one outside of an outright replacement. So I modeled and printed this one in TPU.
It works!
My tub came with a clicker stopper.
First thing I did was replace it with one of these: https://i.imgur.com/DBEGZsR.jpeg
Total cost: $3.99
Works better, too.