I do have a potential fix by hex editing: Firstly use XVI32 hex Editor and select the DragonBallFighterZ .exe and then select the "Replace" tab and type "1080" into the text field, then "26 B4 17 40" (2560x1080) into the hex code field, save the .exe and then launch the game. Make sure the res in-game is 1920 by 1080 and then you should have UltraWide Screen 2560 by 1080. If this doesn't work then make sure the scaling mode is set to "Display" in Nvidia control options and no override is elected.
For "3440x1440" use "8E E3 18 40" instead
For "3840x1600" use "9A 99 19 40" instead
https://imgur.com/a/YSKIx - "Replace tab"
Can't do screenshots at the moment due to issues ill upload a video for proof