I already was doing something similar and have been for what…5 years I think? Anyway, I have an account with Fastmail and my own domain configured with their “catch all addressing” feature, such that anything before the @ doesn’t matter, it ALL goes to me and only me (I’m the sole user of said domain). So I can do things like apple@mydomain, microsoft@mydomain, playstation@mydomain and so on to both keep each address separate from the others and so if there’s a breach or other shady shit going down, I know at a glance who’s responsible and this have some idea of my exposure risk. Ideally though I’d like to be using UUIDs before the @ so specific targeting by guessing something like “I’ll bet his Venmo account is venmo@“ won’t be possible, I just haven’t started doing that yet.

Lately I’ve been combining this with cards via privacy.com to further limit my risk in the event of another data breach, and so far it’s working quite well, though I do have a long way to go to fully convert everything.

As for longevity, Fastmail has been around since 1999 in some form or another, and even made themselves independent again after being acquired by another company through an employee buy-out. https://en.m.wikipedia.org/wiki/Fastmail