I used migadu for a couple of years and they were great initially but over the past 4-5 months, I've experienced really degraded service when accessing email and setting tags, deleting etc.

Over the last month, I started getting login timeouts and that was the last straw. Recently I noticed that they put up an announcement saying that they are running at very high loads due to the COVID-19 situation. I'm not quite sure how people working from home affects normal email (I guess people are emailing a bit more?) but anyways once the announcement went away, I still kept experiencing issues so I migrated my primary email over to fastmail.