Why require a backend? Presumably, that means (in the best case) you end up handling credentials for unknown http end points. In the worst case, the backend sees the data being rendered, and now you have to deal with European and California data handling compliance.

What if the device had a mode to let people connect to an API via a lan connection? That would solve all the privacy issues I just mentioned, and also improve reliability when the internet is flaky. It would also solve the e-waste problem if your backend shuts down.