Quick q: does Eero+ Internet Backup switch automatically, or do you need to do something to switch to the backup?

Use case: I've got a network at my vacation home, which I use to monitor things there (thermostats, cameras, etc). The (cable based) internet there is flaky and I've been thinking about getting a Starlink as backup. But, of course, I won't be there to switch it over. Would it switch automatically?