I think that, if we want something fash-resistant we probably need something by a worker co-op where the whole org has to be fash to be a problem. I’m not aware of such services. A non-profit like Proton is next on the list. I’m not aware of another non-profit email provider. Tuta seems interesting but they’re for-profit.

Also any of those should be based somewhere in Europe since the US regulatory regime is weak and about to get weaker. Email isn’t end-to-end encrypted so its privacy depends on the regulatory regime of the provider.