This might be very good timing for your product - the European Data Protection Board has just out their first guidance after the Schrems II case. It seems to firmly point towards cloud services where the provider can access the data in plaintext as being "unable to have the risks mitigated" from the perspective of international transfers.

Perhaps a straightforward E2EE toolbox could help companies implement their products rapidly so they remain complaint. Clearly this won't help fix issues like Microsoft 365 or GSuite (which need access to the plaintext for email and similar), but it might help some types of SaaS to thicken up their client application and prevent the backend having access to unencrypted data, thus making the transfer permitted.

I just want to echo the above comment around how most customers don't have the knowledge to understand the benefit of this, but hopefully this is changing as we see more strict enforcement of penalties for data breaches. Data is fast becoming a liability you don't want to have the ability to see, and systems like yours offer usable solutions for those who don't understand all the technology, but need a solution.

Thank you so much for this feedback! I missed the guidance you mentioned!