Again, if you were stupid enough to buy electronics with a hard requirement of some random "other-peoples-servers" and the hope they would offer service indefinitely, well, I have a bridge to sell you.
This is nowhere near the first time, or the 100th time.
Verify your electronics can operate fully in offline disconnected mode. And then verify that they can operate in a local mode.
If groups like https://opensprinkler.com/ can do this, any larger well funded company can. Its instad they choose NOT to.