For 2560x1080
Change 39 8E E3 3F to 9A 99 19 40 and
change 00 00 80 41 to 00 00 A8 41
For 3440x1440
Change 39 8E E3 3F to 9A 99 19 40 and
change 00 00 80 41 to 00 00 2C 42
After that, you are either satisfied (you should not be) or you go on with the cheatengine and settings the cheat to change the FOV, since the maximum FOV allowed in the game is 90 and it will not be enough for an ultrawide screen which is displaying the game vert- .... I also don't know if changing FOV with a much higher fov will mess up some cutscenes, or anything like that. For the cheatengine FOV fix refer to a thread on steam community
FOV Fix. Now you can go higher than 90. :: RESIDENT EVIL 7 biohazard / BIOHAZARD 7 resident evil General Discussions
or to the post by CivilWolf on the same WSGF link written above (4th page in that thread).