If you buy directly from Mullvad, they delete the transaction details after two weeks. Sure, your payment procesor knows you’ve bought from Mullvad, but in this case so does Amazon, no?
Regarding Migadu, after extensive research it seemed to be the best option, but man that 20 outgoing emails limit is just so off-putting and the next tier is so far apart. I would be comfortable paying 50-60 euros per year for 50 outgoing emails, but no, it’s either 20 for 20 euros or 100 for 90 euros