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.
Another strategy is to delete your gmail account.
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.