As stated before Uploading to the folder is a MUST-have feature for Proton Mail.

But it could be easily implemented by adding an additional option to the existing filter rule -> upload to folder -> [if, and, or, contains] {"Key"}

• Easier/faster implemented.
• More secure than anonymous uploads or shared folder uploads.
• User doesn't need additional automation for simple tasks -> Increases efficiency -> saves time -> can be sold :)