Ask HN: Email client with an opt-in inbox?

I'm tired of a cluttered inbox, but also tired of:

- manually unsubscribing from newsletters I don't remember signing up for

- managing folders, tags, etc.

- allowing for-profit entities the power to divert my attention whenever they want

Are there any email clients with an opt-in inbox? Meaning all emails go to blocked/triage/queue unless I specifically approve them for my inbox, or similar. I want my life uncluttered, I want to be stingy with where I place my attention.

I remember vaguely hearing about this kind of email inbox over the years, but I wasn't able to find any existing providers when I went to search for one this morning. Is anyone using a system like this, any suggestions?