I do use org mode for PKM, it's great. Used org roam for two years, but I wasn't really using all of its features so I went over to using denote which works well for me. I am not a student, however, I do read scientific papers and articles for my work and I am mostly using org noter and citar for annotations/syncing and bibliography management. Sometimes I simply take the note without any extra fuss also. I recently stumbled upon youtube sub extractor which let's me get a transcript of a youtube video as text in emacs. Great stuff. This is of course only scratching the surface as far as workflows go. Hope it helps, if onøy a little!