I like Fastmail but I'm starting to feel that the subscription cost is a bit overpriced for the way I use it (just IMAP email - not using the app, calendars, contacts, file hosting, ...). I've researched and found some other independent paid email providers that are significantly cheaper, although I suspect most of having a low bus factor with just 1 or 2 people operating them.
It's likely that regular Fastmail users are subsidising their AI costs. I've talked to several people who were a bit shocked when Fastmail decided to complicate their offering with the current hyped trash.
Are you thinking of some other company? The most Fastmail has done in LLM directions is offering an MCP API: https://www.fastmail.com/blog/an-mcp-server-for-fastmail/.
i have been using posteo.de for the last decade with no problems at all. Exactly the feature set you use. I only recently started to use their Caldav stuff which works.
I recommend them.