Furniture knobs as a towel hook
The range of hooks for the bathroom is not exactly great, especially when screwed.
Ever looked at furniture buttons? Large selection, mostly with M4 thread for screwing on from behind.
For this simply buy hanger bolts - the end with metal thread all the way to the stop in the button, then into the wall: with a little luck, the screw clamps without dowels in the tile joint - it worked for me, "pre-drilled" I have with a screwdriver.
If that does not work and there are no holes in the tiles: 3-4mm dowels should still have room in the joint. Screw in thin chipboard screw, pry head off (Caution: Risk of injury: Wear safety goggles, "piano wire" pliers and pull over the screw a plastic bag so that the parts do not fly around). Then glue the screw in the furniture knob.
