To me a "burner" is a phone you use and discard. I suppose by following these steps you could discard the phone without much concern for what could be retrieved

To me a "burner" is a phone you use and discard. I suppose by following these steps you could discard the phone without much concern for what could be retrieved but the same would be true of a phone you can choose to wipe before discarding. I'm a little surprised using a VPN isn't on this list, in addition to, not instead of anything on the list. The list pretty much limits communication to encrypted channels but adding a VPN would conceal even which channels you use (not from shoulder surfing).