There's none. That's my point.
Right now, I can only choose between unencrypted or insecure alternatives or proprietary solutions which cannot be publicly audited like Tuta, Proton, Infomaniak and more.
I want out of big tech, but I just don't see where to go exactly.
If you find you can raise awareness about this unfilled void in the market to your clients and community, I think everyone will benefit greatly.