I admit that I expected more. They really did the minimum, as in, anything less should have been illegal. It is praiseworthy, but it is unfortunate that it is.

Seeing that, I expected the ability to build and run a custom firmware, like with an Android device with its bootloader unlocked. But it is not that, and they didn't open source their app either.

What they did is that they removed dependence on their servers, and opened their device to be controlled by third party apps. That is, they let users use their device past its end of life, including when the first party app will stop being maintained, but not to the point of letting user add features.

In understand why they would do that, they don't want users to backport features only available on their latest models that are sold at a premium, therefore competing against themselves. After all, the value in smart speakers is not the sound producing device, which I think is a problem that has been solved more than a decade ago at the consumer level, it is all about software features.