You definitely can't just jump into zettelkasten, but it is actually used in various modified forms. I've been doing so for years and know of a number of others that do as well.
Yeah, most of the academics I know have a pile in OneNote or mountains of paper notebooks. I don't know if zk is good for research tbh, but I do think you can take some ideas from it. I personally use "bullet journaling" + a modified zk method.
I'd be curious to hear what the "highly productive" academics you know use.
