Do I leave FOV hdeg 4:3 as it is or change it to 16:9 since thats what i play on?

 

Leave at the default type (4:3) as this is what the game uses. Only change type if you want to convert between types. Say you want the FOV to be 103 like in Overwatch, then select Hdeg Res and enter 103, then check the output for the Config FOV to see what you need to configure in Apex to get this FOV.