A prominent open-source dev publishes their findings as to what's going on with Starfield's performance, and it's pretty darn strange.
According to Hans-Kristian Arntzen, a prominent open-source developer working on Vkd3d, a DirectX 12 to Vulkan translation layer, Starfield is not interacting properly with graphics card drivers.
Is poor game optimisation a minor detail?
Yes, have you even played bg3? It stutters way way more and is plenty enjoyable. They both did a mid tier job of optimization.