Its a long journey, but totally worth it. When I chose to go fully self-hosted, I had around 1,200 accounts and passwords.
First I used a temporary fake emailnsite to change my email and all the personal data I could from all the sites I wanted out of my life, then closed each account. Did a checkout wherever I could too.
Then went into each account I wanted to keep where I was using a gmail address, changed my email to an alias (proton mail) and created a new random password for each (Bitwarden self-hosted).
I'm down to about 100 accounts, including everything in my 2 jobs.
The level of freedom I feel is unspeakable.