Basically, something like Bitwarden Send or Firefox Send:
https://bitwarden.com/products/send/
https://send.vis.ee/ (Fork of the discontinued Firefox Send)

Following scenario: You just want to quickly and privately share a file with someone. Currently you would have to upload it to Proton Drive, manually create a shared link, and remember to manually delete the file.

It would be really convenient to have a shortcut for uploading an expiring, immediately shareable file.

This is the feature that could enable me to stop using bitwarden at all.

Integrate pass with mail to allow for sending passwords via encrypted mail with expiry. Some other password managers have a send feature which allows the user to share passwords or secure notes with others over the web that are password protected, limited access, or have a time expiration. Since Proton already has email that includes many of those features, it would significantly simplify this process.

I want to be able to send someone a file or some text without storing it indefinitely in Proton Drive. Basically Bitwarden Send/Firefox Send.

I want this to be as easy as it is in Bitwarden. Upload a file or type some text, set an expiration date, receive a link. Share this link with someone and forget.

I especially want the option to write some text instead of uploading a file. This is useful when you want to share sensitive data like a password with someone over an unencrypted channel. Right now this requires you to create a text file to upload first.

More information: https://bitwarden.com/help/about-send/