>In this case, we actually aren't being ambitious enough. Why are we having a system where we give out phones every 12 weeks to each homeless person? We'd probably save money for the program by developing some sort of dedicated device designed to be harder to steal or lose. Maybe a high-autonomy low-powered KaiOS smartphone that can be attached as a strap? It's not like the current devices are working.

You're putting the cart before the horse. The far simpler solution is for the government to provide the homeless with email. Now the auth can work however you want.