Here's an idea: not buying "smart devices" that turn into fancy paperweights the second they aren't connected to a WiFi network.

• A scale doesn't need to connect to a server.
• The lights in your house don't need to be connected to a server.
• Your fridge, etc.

If they do, that's for something completely different than what you bought them to do. And if there's no FOSS app to control those extraneous features, it's a black box.