Espresso Stalinist has their flaws, but they hosted an interesting write-up about it https://espressostalinist.com/2014/08/24/the-doctors-plot/

Riumin’s actions seem really suspect throughout the events

edit: oh and here is Bill Bland’s book on the topic. https://www.marxists.org/archive/bland/1991/10/doctors-case-death-stalin.pdf

I will say the “rootless cosmopolitanism” campaign is pretty tropey and gross