My grievances with Proton

The issue is that using my own domain, at least for sign-up aliases, is that all aliases can attributed to me by virtue of being the only person that uses that domain. My threat model includes protecting my information from being aggregated by cross-referencing dark web leaks, where email addresses and phone numbers are the most common linkage points. Say, for example, there is a leak for abc.com and xyz.com. abc.com knows many things about me that xyz.com doesn’t know and vice-versa. A malicious actor in possession of the data of abc.com can initiate a search for other leaks containing an email address, or my email domain, and find more information about their victims across leaks. This is what email aliasing can avoid, and why I used them in the first place.