decrypt

Fastmail as well. I just paid for 3 years which amounts to 3.11 USD or so, per month.

May I ask what Thunderbird local storage means? Does that mean that emails are delivered and stored on the device, vs on a cloud server?

What address did the email come from, and what do the headers show? Anything to indicate it's a spoofed email?

Very much this. I see users getting locked out of Google account often, or Google changing their policies (like the recent change of free G Suite accounts to premium ones) which would mean you'd be locked out of most accounts.

I am not aware of any truncation, but best to ask their support and/or ask on their community forums.

Any standard email host with IMAP access and a custom domain will do. I like Migadu.

Both of them. The domain and the ability to remove trackers are why I signed up when it initially launched.

This service is not ideal for spammers because it is not possible to initiate sending of emails using Duck at the moment. It's only for receiving and responding to incoming emails.