Seeing speculation that this new Obsidian Fallout game will be on Unreal 5 because Obsidian devs are already familiar with it and recruiting new hires during development will be easier and faster. That would be a huge mistake though, most of a Fallout games' late life sales legs are due to the strong modding community. Creation Engine modders are rarely familiar with Unreal Engine and Unreal Engine is notoriously difficult for modders to begin with, which is why most Unreal games have few mods. The Unreal Engine game with the most mods is Stellar Blade with 2.7k mods (most of which are outfit mods and reshades, the easiest things to mod), Fallout 3, New Vegas, and 4, have 17.1k, 41.2k, and 74.8k mods respectively, all way more than any Unreal Engine game.
Better to have a small Bethesda team go in and spend a month or so training Obsidian on Creation Engine 3, which was made for Elder Scrolls 6. A month of training time is way less costly than losing like 90% of the Bethesda modding community who are familiar with Creation Engine already from Fallout 4.
