For those who are interested in cheaper lighting solutions than lumen, I would like to point out this topic here:
SSGI is worse in unreal 5? - Development / Rendering - Epic Developer Community Forums (unrealengine.com)
In ue4, I managed to get some nice ssgi lighting through the use of console commands. It was slightly noisy ssgi, but smear free, and very cheap. However in ue5, I cannot achieve such a good result. In UE5, ssgi is more noisy, locked to a lower resolution, and more expensive for me due to having certain performance enhancing settings removed.