Here's a video from Dr. David Barker, who leads the Rosetta@Home project, describing how that project's computing has helped COVID research. https://www.youtube.com/watch?v=ODEIN5V3yLg
I hadn’t seen that video before, but it’s not quite what I’m looking for; it seems that video was made while they were still working on the project, and they were looking for a way to “get it out into the world”. Is there a sort of post-mortem analysis of what the project achieved / is still achieving now?
Ultimately, what distributed computing projects provide is processing of data to facilitate scientific research. Most projects publicize scientific papers that make use of their data, like this blog post and the paper linked therein. In terms of post-mortem, that's difficult to have while COVID is still an ongoing field of research.