Thirded
I assume 3M makes those inserts for their hooks because it’s difficult to mass-produce cheap hollow objects with a firm flat back.
We don’t have that problem.
I have stuck all manner of things to the wall with command strips — power strips, 3D-printed hooks, boxes… whatever has a flat back works fine.
We pushed “the guide to getting it on” on our children at a relatively early age and invited them to discuss, which ensured they would never, ever, ever ask us anything about sex.