Game developers are always trying to push the boundaries. The only game engines without performance issues are ones hardly being used.

I am sure that many of the issues were a skills issue as well.

What engine do you recommend?

Do you have any source taking about GC caused performance issues in those engines?

I mean, you can always add enough triangles, shaders, entities, etc... to make any engine slow to a crawl... Anything that pushes state of the art will have more performance issues than something that doesn't.