I mean, HomeAssistantOS has a GUI in the browser with an upgrade button that appears when there's a new release (which is frequent -- actually my biggest complaint about HA is how fast they move and that I can't configure HA to just install the updates as they arrive, and I have to actually click the button. Horror.)

It performs a backup whenever you perform a release, so if the SD card gets corrupted.. just follow the install instructions a second time and upload the last backup?

That's it for the upkeep, other than dealing with 3rd party APIs that change and make things break, but that's not HomeAssistant's fault.