Ray at DCRainMaker posted a video discussing missing and half baked features on the initial Mavic 3 release. It also includes a link to a spreadsheet of 42 items that will or will never be implemented as well.
Some of the notable items missing is ActiveTrack, MasterShots, Spotlight, and POI (these are scheduled to be implemented in Jan '21), and no "Pro" settings for the secondary camera (tele). As with the MA2 and A2S, waypoints will not be available. The 4G dongle will not be sold in the US/UK/EU due to government restriction on 4G use.
22 things are mising.... wow