I've used Migadu for several years after switching from Google Apps. Technologically, I've been pretty satisfied. I have a lot of custom domains that I may want to use different users/mailboxes on and Migadu's pricing model makes that pretty easy.
In 2020, there was some turmoil with Migadu where they nearly (or completely) doubled their prices and didn't communicate it well. I was paying 45/yr then abruptly started paying 90/yr on the same/equivalent plan. They also took away a couple of features purported to be the cause behind some performance issues they had. During that time, their service was strained. Many users, me included, didn't realize there was an issue until no e-mail was received for days. Support just said "sorry" and that there was a post about it on their website. I think this situation soured a lot of users. You can read about it, including some of Migadu's response, if you search this site, reddit, and lowendtalk.
I agree with you that their speech codes in the TOS are sketchy, ambiguous, and trite. I'm not sending or receiving any e-mail like that, but I don't trust contemporary definitions for those topics. I've been considering another provider when my subscription is due for renewal because of the price change.