I am having the same problem, though I'm not sure about the task manager one. Every time I open the game it'll load but then stop, and nothing opens and I tried everything, uninstalling it and reinstalling it uninstalled steam and reinstalled it, to just copying and pasting the _renpysteam into "Renpy" folders that was already on it but still nothing
Edit: Ok I finally figured it out, if you have a Windows and have played other steam games go to Windows C/Program files(x86)/Steam there search the file _renpysteam, there should be two of them, a .so file and a .pyd file, copy and paste them (ITS MANDITORY FOR BOTH THE .so AND THE .pyd FILES) into the common folder, (Windows C/Program files(x86)/Steam/steamapps/common/doki doki literature club/renpy/common) if it doesn't work go to task manager (ctrl+shift+esc) click more options and it will bring you to a list of software that opens up after a restart, you wanna click end task on a few of them, after like 3 or 5 it should work, if it doesn't or you have a mac then idk