Yeah the lumen coverage looks good (it should look similar to the scene), you're using hardware lumen so it's going off the actual geo instead of SDFs and cards that software lumen uses, it'll be fine for a portfolio project or a hardware raytracing only project.
Lumen does a lot in screen space that can mask issues until they are on the edge of the screen where screen space fails, it also looks inconsistent even if it's doing a decent job of hiding issues. Id check the lumen debug views under lit and make sure it isn't missing coverage. It matters more if you're using software…
One large piece with a hole in the middle is going to cause issues with lumen, it doesn't like closed in concave areas like that. But if you're not using lumen or DFAO, it'll be fine. 4.6k tris is pretty light.
I’m not sure if I’m looking in the right place according to your explanation, but this is what it looks like when I switch to the Lumen Overview. I’m using an additional rect light, and if it’s turned off, the scene looks like the top image.