It would be fantastic if I can choose a Folder within "Shared with me" ¨Vault".
With this we don´t have to download the file to the mobile / tablet, go to the Proton Drive app, go to the desired folder in the "Shared with me" ¨Vault", "click" on the "Upload" button and then select the file you want to put in the share folder.

With this it would be as simple as "click" on the share button of the file, folder, whatever, and then select Proton Drive and finally the folder where you want to upload the file.

I don't know how encryption is implemented, but I think this is easier and could be a workaround (and just a workround) to the "organizational / familiy / duo " folder. I think itś not very elegant but functonal

Regards