Why would you pick unreal? It seems a lot of games made in it suffer performance issues. In my mind its a really unwieldy engine. (ofc, because its so feature packed, and perhaps because i am no professional engine dev :-))
I like Unreal because it's really quite intuitive and ergonomic for larger productions, fairly well documented, and has some of the coolest tech in the industry. Their rendering pipelines are beautiful and a joy to work with and I could rant all day about my love for Nanite and Lumen. It is light years ahead of Unity and much easier to understand and modify than Frostbite.
I will say that Unity has better support out of the box for custom shaders and compute than Unreal (and Frostbite).
Now, you mentioned performance. Funny thing: performance has been my primary professional concern for the last six years of my career. Unreal itself performs very well if you use it correctly and has really good documentation for best practices as well as amazing tools for measuring performance and indicating what is wrong. The tools in Frostbite were very lackluster. Unity has some fairly good stuff. Unreal feels so far ahead.
I believe the reason there are more visible Unreal games with performance issues is because there are a lot more noteworthy ambitious productions in Unreal. That means games which push what they can deliver, and often don't quite get there. And for smaller productions it's likely just a matter of less experienced teams not following the best practices or cranking settings up to 11 without proper performance budgeting.