[LinuxBender]

you have to jump through hoops with third-party tools

I personally find it very easy to send PGP encrypted emails with Thunderbird. [1] Thunderbird makes encrypting email platform agnostic. I can switch vendors without losing my ability to maintain E2EE with friends and business partners. I have been able to get non technical friends and lawyers to use Thunderbird and PGP as they just follow the picture instructions.

This is just my own silly opinion but I would never personally rely on a platform to manage "E2EE" for me. If I do not generate and control the keys then I can not seriously call it E2EE. As such I do not consider WhatsApp and Signal to be end to end encrypted. That's just my personal opinion but perhaps I am just a bit touched in the head.

[1] - https://www.linuxbabe.com/security/encrypt-emails-gpg-thunde...

[malfist]

Even then, your content is encrypted, but not any of the metadata.

[LinuxBender]

If I need to protect metadata then I just have people SFTP encrypted files to me and keep everything off of all the shared platforms all together. For me personally that's a one-off as I rarely have such a need.