Had to install vcrun2022 following these instructions:

so for future posterity, here's how to do it through the GUI
hit the super button, type protontricks to open up the GUI applet
select the game in your library you want to add the library for and click ok
select default wine prefix, ok
install a windows DLL or component, ok
you'll usually just need vcrun2022, with the title "Visual C++ 2015-2022 Libraries"

Source: https://www.reddit.com/r/linux_gaming/comments/o7uubb/how_do_i_install_the_microsoft_visual_c_runtime/

Protontricks complained that SHA256 didn't match, but URL matched official Microsoft installation page, so it was fine.