I think they make it pretty clear the problem is with their inability to change the endpoint (i.e. the URL). Switching from lambda to something else could be a

I think they make it pretty clear the problem is with their inability to change the endpoint (i.e. the URL). Switching from lambda to something else could be a pain in the ass but they'd be hitting their own domain and changing where that points is relatively trivial. Right now they have clients out there hitting a Firebase endpoint that they have no control over and that they can't update quickly.