1GB at 30Mbps = 4.5mins.
How urgently do you need that new housing development 200miles away from you on your phone map?!
Are phone manufacturers still doing whole rom updates rather than incrementals? 3GB at 30Mbps (15mins) and another 15mins or so to actually install... not something I'd generally do while out-and-about, rather it'd be an automatic/background download and installation that happens overnight while charging.
Youtube 1080p 60fps has a bitrate range of 4.5Mbps-9Mbps, that shouldn't buffer at 30Mbps, and is there really a need for more resolution on a 6" screen but if so, 1440p 60fps at 9-18Mbps or 4k 30fps at 13-34Mbps should both be fine.