Un package existant a déjà été installé. Tentative de mise à niveau du package installé...
Mise à niveau disponible introuvable.
Aucune version de package plus récente n’est disponible à partir des sources configurées.
Ah, that sounds like it hasn’t done anything… I imagine you should have Visual Studio Installer somewhere in your start menu and you should be able to alter the installation(s) from there to add the three workflow items mentioned above.
Unfortunately, I removed completely OCaml from Windows, and I do not have a strong enough motivation to test if your solution works. Now, I am using WSL to learn OCaml.