There's an Eevee update in the works that includes some Lumen ideas, real emissive materials for instance (iirc). Even for now, you can dive into the options and enable some stuff like refraction that defaults to off for the folks with less GPU.

I have no idea, I only use blender rarely and almost never render. eevee is intended to be compatible with cycles, I would guess that if your scene does not depend on the advanced lighting that a forward renderer like cycles enables it could replace cycles. I also expect it to be as good, if not better than ue5 as it does not have to hit the framerates that ue5 has to achieve.