Fallout 76 got an Important PatchTempo: Dec. 13, 2018 Dal: SCDKey
Fallout 76 Bethesda Key EU had an important patch that provided a number of expected solutions specific to computers, including 21: 9 compatibility. But do not get too excited, very broad-based users still do not work like you want.
The official 21: 9 option allows the game world to fill the screen for the most part. The problem is the user interface, which spreads and distorts next to the larger resolution. These include HP and AP ads, mission tracking tools, loot and inventory. There are even invisible visual disturbances around water animations.
As already mentioned, the official version has exactly the same problems as the previous edition .ini. It was the same in Fallout 4, although the mods finally fixed it. There is also an unofficial 21: 9 mod for Fallout 76, and although it has its own problems, the interface is at least correctly adapted.