Email Setup Advice Wanted Please

Help with an Email Setup Wanted

Hi, I bought Proton Unlimited in an effort to De-Google and move away from Gmail (used it for over a decade, i get a lot of spam, trying to be smarter digitally). It's got way unoragnised and i want a clean slate.

I am just not sure how to set up my new email because I have read alot of conflicting advice and posts, so I'm confused.

Ultimately, I want security and also simplicity because I have been way overthinking this.

Priorities are simplicity, privacy, security and a set it and forget it system.

My ideas:

1) Just use my @proton.com address for everything.

2) Use simple login alias subdomains, for example @surname.simpelogin.com for official things and so on.

3) Use a custom domain (not sure what I'd call it) and just use this, being careful what I sign up for and using aliases to categorise things (banking@mydomain.com) and so on.

Open to other ideas, thank you in advance.

Any other advice on keeping accounts secure, keeping things simple and organised etc would be appreciated!