Hi, here is a "strong" hook for glueing or drilling to a wall. The drill holes are not extruded through the whole model in case you want to glue it. If you want to drill, drill trough the backside of the model or cut them in Fusion360. The holes are 4 mm in diameter. I can't say how "strong" this Hook realy is, but I'm using it to hold a bathrobe and it holds perfectly fine even when wet.

Feel free to leave me some feedback in the comments and please post any prints.