Here is an incredible Gmail tip to quickly unsubscribe from all the companies you may have unknowingly subscribed to.
Open Gmail in a web browser.
Delete everything in the URL after /mail/ and replace it with /mail/#sub
This will open a list of all the companies you are subscribed to for emails, together with an unsubscribe button for each one.
I'm almost there... moved everything important over to protonmail a few years back, just haven't deleted my 20 yr old gmail account yet because it's tied to an old phone that I still use for apps and taking cat pics, and in case there's something I forgot to change.
I get roughly 1 or two emails a month from places I'm not willing to give my good email to and that's about it.