UE5 is not a generation head of anything. Red engine looks greats and provides several unique features. Red engine was constantly worked on like every other AAA engine and it gets better non stop.
I think this is important to emphasize. Epic Games are very good at marketing and giving cool names to features that aren't that new or singular to UE (like Lumen or Nanite). Now, I don't want to trash Unreal Engine but it's not like other engines are lagging behind in any way. id's very own id Tech is anything but lagging behind. Frostbite is also pretty much up-to-date. Capcom's RE Engine, while not implementing stuff like path tracing or dynamic LOD like UE, is just awesome at scaling toward lower-end hardware while still looking good and running well. That's one of the areas where Unreal Engine sucks ass and has sucked ass since UE4.
Look at the lighting solutions implemented in the Gran Turismo engine, that is by no means lagging behind anything Epic are doing. And of course Naughty Dog's and Insomniac's engines (maybe they share some code base?) are also on par with Unreal. And I'd say, from a feature point of view, Red engine is also on par with the current version of Unreal Engine.
What you get when you buy into Epic's solutions is that they (hopefully) have your asset pipeline figured out for you, they will take care to evolve the engine for you and have tools surrounding the engine (UE Editor is the most famous and integral one) ready. They have multiplatform support and build tools ready for you. But shit still breaks, you still have to have a team of programmers trying to fit your "vision" into UE5 and maintain it and "baby sit" the engine from time to time. But if you're a paying customer, you get support from Epic and Epic acts as your "R&D" department that gives you an engine that is fairly up-to-date with the progress in graphics.
That being said, UE5 isn't a solution that fits all needs. For some types of games and some types of projects, it's much less of a pain to just roll out your own shit.