The Firefox Account has no communication options and does not send promotional emails: https://accounts.firefox.com/settings
Not sure what lists you're subscribed to, but they aren't part of this account. What mailing lists have you subscribed to or what service are you talking about?
https://old.reddit.com/r/firefox/comments/fggla9/get_the_f_o...
Check the bottom. When you clickthrough the Email preferences link, you're presented with a list of several email lists you can subscribe/unsubscribe from.
Edit: I was subscribed to a couple lists I never directly opted-in to receive, though I never received any emails from those lists.
Btw, I'm not against looking at FF again, but looking at this changelog and recent product direction, they honestly feel lost.
Not mentioned in the changelog for this release is that in the URL bar, when I start typing and the suggestion list drops down, the first result is now highlighted in an eye-destroying bright green (even in dark mode, which I'm using).