Checkout the issues list of the open-source projects that you care about on Github, pick the ones that interest you and submit pull-requests for them. You mentioned rust, you can join the #rust channel on irc.mozilla.org when you get stuck, you'll find very helpful people there.
Most of the 3rd world lives with dumb phones that work well for the tasks they are designed to perform which are to make calls and send text messages. The device in question is not able to perform any of the above named tasks without running into problems. This would frustrate anyone no matter where they live