Old stretched res (FOV slider involved)

Not sure how this person did it but I was wondering on how to recreate this (OG) stretched resolution effect and bind it to different buttons as this person has. It actually changes your ingame resolution and make the character FOV a bit higher matching on how it was in Chapter 1 of fortnite. Example listed here (uncapped_MedalTVFortnite20230720022113). How is this doable and how can I recreate it for my map?