All good, all the best.
another source of issues specially in big spaces with lumen is
virtual shadow map cache invalidation #1 , vsm page pool #2, and reflection capture resolutions.
material complexity is a basic one i forgot to mention.
also check the significance plugin by tom looman. i’ve made my own but haven’t published it yet.
#1 vsm invalidation is actually very impactful.
there’s a nice doc about it somewhere, i think is this one
#2 the page pool is also important. increasing it is not really a solution. because if you run out of vram you run the (almost certain risk) of tanking your performance. and increasing the pool will reduce the vram available for other things (afaik) and not all the users have the biggest gpu on market.
you can play around with the world quality
How do I lower the graphics settings for the editor? - #8 by Blackforcedragon
this is kind of the 1st stop for isolating your performance loss. vsm and page pool issues are sensitive to light and shadow qualities.