Ask HN: Best system for emails and passwords *SOS*

Hey HN, I recently realized I was in need of a hard reset. I completed my mandates, and quit my jobs - a three month OOO to take the time to introspectively audit and assess many aspects of my life. The one thing I realized was actually taking a burden on me psychologically was this looming and never ending mental to-do list weighing down on me, especially in terms of data and information overload.

Something I've been meaning to do for YEARS, is finally build and implement an optimized system for handling many different usernames, accounts, and passwords. Ideally, I want a system that might take me time to implement, but that will almost run autonomously and require minimum steps once set up.

I fell on a few other threads that portrayed a version of this ideal system I've longed for: create custom domain emails for each service requiring a username and use one of the password managers (yes I'm still not using one and my mental hard drive is on the brink of croaking from the dozens upon dozens of various handle names and passwords I've stored mentally. This is what I'd like to know assuming this is the best system - open to other solutions of course.

(1) best way to register and host new domain for this purpose, and then use a mailserver such as protonmail? I like this strategy because it will force me to be more selective of where and what services I register for since it would require a few steps and also I can easily control and audit the culprit if/when I run into a spam issue.

(2) best paid for password manager?

part of my initial process was unsubscribing my various emails from different services as well as making a spreadsheet of all my usernames, passwords and sites they're used on. I'm ready to finally lift this burden off my back. I appreciate any advice given to me, you don't know how much you are helping me in bypassing any OCD, perfectionism, and need-to-know tendencies I may possess.

- neighbourhood friendly brain