there is one at Home Depot that is a black bottle inside a plastic bag, contains hydrofluoric acid that eats all the organic material clogging the drain. etched some of the metal of the plug when I used it, pretty strong stuff. only used half a bottle, drains been clean since.
always check the opening for hair and debris, almost always the culprit. I have a set of needle nose pliers in the bathroom for this specifically.
the hydrofluoric ones absolutely do work if snaking doesn’t.