Don't make it sound like it's that hard to make a site-unique password scheme. And all it takes is buying a domain name, and you can have unique site-specific login emails as well. Even if one of the sites gets hacked and your L/P are in plaintext, it would take an actual person intentionally targeting just you to even have a hope of noticing your scheme, let alone figuring it out. Sprinkle in some 2FA and there's no way anyone is finding another accessible account before that site auto locks for bad logins, and/or you notice all the notifications thereof.

Or you can put your entire life worth of passwords into the hands of a company dedicated to making as much profit for as little work as possible, and hope it works out for you.