I’d imagine it’s even harder since it’s not their own engine this time around. With an in-house engine you get a team that knows the engine inside and out and can help squeeze out performance. Using Unreal Engine comes with a lot of tools that can make the art side easier so it seems like you’re saving time/money, but optimisation is arguably harder because you don’t have the same kind of internal expertise to optimise throughout production. I’m sure a studio their size can get some help from Epic, but that’s going to come with it’s own drawbacks.