More like: paying someone to maintain the hardware.

Anyways.

Just FYI, your mails with a provider like Proton are not E2E encrypted unless you exclusively wrote with other Proton customers (in which case I assume they are. No idea). Otherwise it's just encrypted at rest.

I dint really see the benefit over doing it completely yourself, not even offering metadata to a provider, and also having encryption at rest, while maintaining full compatibility with mail clients 🤔