Using your thread to ask: What recommendations do people have for a
build that's best for heavy org-mode use? Of all emacsen which is the
best drive for Org?
I don't have any specific build-time recommendations for org-mode, but I can wholeheartedly recommend the built-in 'leuven' theme for org-mode work. I normally don't go in for light themes, but this one has so many nice little touches to spruce up org-mode elements I find myself switching to it from my usual dark doom or modus themes when working on org-mode projects.