With all the different kinds of controversy that Google is choosing to get itself into lately, I've stopped using Google Chrome, deleted all of its saved data, and deleted data for a bunch of other Google products (YouTube, Google Pay, everything but Gmail). My web history, location history, and bunch of other things are set to "paused" (everything that Google allows to be paused is paused). I deleted third-party access to my Google account. My ad settings are set to not be personalized.

I use uBlock Origin, HTTPs Everywhere, EFF's Privacy Badger, and Canvas Blocker on Firefox, but I also have Firefox set to clear all my history, cookies, and other browsing data when I close it. I also use a router-based ad-blocking via Diversion (formerly AB-Solution) and pixelserv-tls as well as dnscrypt via dnscrypt-proxy.

Obviously, Gmail is the last holdout.

My question is: with just my Gmail account, what can Google know about me or do to me? My only concerns with leaving Gmail for something like FastMail or MailFence are the potential reliability issues (both in sending email reliably from my own domain and accessing it as often as I do now). It'd be nice to have both end-to-end encryption, and encryption, but given how powerful a $5 wrench is, it's probably wishful thinking.

(For completeness: I stopped having a Facebook account. I log into my LinkedIn account once a year. I log into my Twitter under five times a year. I don't have the mobile apps (first-party or third-party versions) with any of them. I don't have a tinfoil hat, but I have bought https://www.amazon.com/dp/B01I497JAM/ for someone before.)