There are a lot of manufacturer-agnostic smart home devices out there, and with just a tiny bit of research online it’s not difficult to avoid anything that is overly tied to a cloud service. Z-wave, ZigBee, Thread/Matter devices are all locally controlled and don’t require a specific companies app or environment — it’s only really the cheapest, bottom-of-the-barrel WiFi based devices that rely on cloud services that you have to be careful of. As with anything, you get what you pay for.

Even if the Internet were destroyed tomorrow, my smart door locks would continue to function — not only are they Z-wave based (so local control using a documented protocol which has Open Source drivers available), but they work even if not “connected”. I can even add new door codes via the touchscreen interface if I wanted to.

The garage door scenario can be a bit more tricky, as there aren’t a lot of good “open” options out there. However, AFAIK all of them continue to work as a traditional garage door opener if the online service becomes unavailable. I have a smart Liftmaster garage door opener (which came with the house when we bought it), and while it’s manufacturer has done some shenanigans in regards to their API to force everyone to use their app (which doesn’t integrate with anything), it still works as a traditional non-smart garage door opener. The button in the garage still works, as does the remote on the outside of the garage, the remotes it came with, and the Homelink integration in both of our vehicles.

With my IONIQ 5, the online features while nice are mostly just a bonus. The car still drives without them, the climate control still works without being online — most of what I lose are “nice-to-have” features like remote door lock/unlock, live weather forecasts, calendar integration, and remote climate control. But it isn’t as if the car stops being drivable if the online service goes down. And besides which, so long as CarPlay and Android Auto are supported, I can always rely on them instead for many of the same functions.

Some cars have much more integration than mine — and the loss of those services may be more annoying.