UE doesn't see my VS installation

so, I have a project that a friend gave me, but when I try to open it, it tells me that I need to install visual studio 2019, BUT I do have it installed (under "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\ ")

so, at this point I tried:

  • installing VS with the download manager (that UE launch anyway), but the visual studio installer recognize my already-existing installation and doesn’t do anything
  • re-installing UE and then VS
  • moving the project file and my UE installation to the same drive than my VS installation.
  • seeking online for help, but found nothing

Furthermore, when I launch a blank blueprint project and go to:

editor settings > source code > source code editor

the dropdown menu doesn’t gives any choices
(despite me having 3 versions of VS and 2 of VSC on my computer)