Disagree. At least with those providers you have encryption at rest and with PM you can also use pgp.

You can claim that is "privacy theatre" since they can clone and archive unencrypted emails in-transit. True.

But doing that severely goes against their business model, specially when you are a paying customer. It is a trusted relationship in that respect, but at least the incentives are on your side.

Using gmail or other mainstream providers is strictly worse in every way. And you know that they are actively scanning your unencrypted emails not just for spam prevention, but to sell your data and to give your up to Law Enforcement.