My current wifi is named, ForbiddenPlanet. The new Tp-link mesh router offers 2.4 and 5 GHz with band steering. This means that each smart-home device is able to choose the frequency that it finds best depending on its location within the apartment and its capabilities.
Furthermore, I can turn on a guest wifi network containing both frequencies as well. It's presently called PlanetVisitors. People connected to this alternative network cannot accidentally mess with anything because they are on completely different wifi. I usually keep this turned off. I can simply make a request to my Google Assistant when friends or guests arrive.
This QR code allows access to my guest network. I printed a few, little cards to hand to guests during their first arrival. If they don't know how to scan the code, they can simply add the information found written on the paper.