Sounds quite interesting. However the article reads a bit like an ad.

I use a self hosted Nextcloud which also has many of these features.

will be interesting to see how this develops over time.

Looks like a viable alternative to fastmail. I've been with fastmail for ~15 years. I've loved it for a long time but I'm approaching 30gb of archived email and the pricing for 60gb is obscene.

That said, choice of email provider is a big deal. I have a small business et cetera and the idea of changing provider kind of fills me with dread. One of these days I'll have a closer look at alternatives but today is not that day.