Setting tracking protection to on also forces Do Not Track to turn on, which can be counterproductive if you want to avoid fingerprinting. I prefer to use uBlock Origin and Privacy Possum.
Switch to uMatrix if you have enough know-how to fix websites that break. It is the single best plugin I know. I use it on Firefox mobile and it speeds up websites faster than AMP.
I used the advanced mode in uBlock Origin with default-deny on all 3rd-party frames and scripts for a while. It does get tiring after a while to go in and noop sites to fall back to the filter lists, and reload. Rinse and repeat until the site works. It's especially annoying on mobile.
It especially tends to break online payment solutions, I've had more than one purchase go haywire, including one where I just got the "order confirmed!" page instantly, without ever entering any payment details. Their support guy was a little bit confused about that one ;-)
So now I put my trust in the block lists, Privacy Possum, Decentraleyes and Firefox' built-in fingerprinting resistance function ("privacy.resistFingerprinting" in about:config).
The latest additions are Multi-Account Containers and Temporary Containers. Every new site opens in a sandboxed temporary container that gets deleted 15 minutes after I close the last tab in it. This discards all cookies, cache, everything stored about that site, except browsing history entries. Think of it as a cookie autodelete on steroids. I have permanent containers set up for sites where I want to store the login or other information, such as HN or FB. Each site can only see its own container, so there's no cross-site tracking.
You seem to be a privacy expert. PrivacyWall will not break these payment solutions. We'd love your feedback on PrivacyWall. It's free for download at http://www.privacywall.org
uMatrix is cool, and I respect the hardcore approach to privacy, but it's a ton of work for most sites. I found there's usually a lot of trial and error trying to figure out the minimum combination of things needed to get the site to work, during which I usually enable something I wish I hadn't and wasn't required anyway. On top of that, web sites change, a lot, so getting the right mix is usually temporary.
I feel the community maintained filters, while possibly imperfect, will be better than my custom filters especially when my patience runs low.
uBlock Origin gives a similar matrix with "I'm an advanced user" on. I have a personal rule of never fully whitelisting a domain, or even a single page. The only matrix level rule I have is for one of my bank accounts that requires an iFrame to make a payment. Any other site that breaks, I leave.
Firefox Mobile on Android is the best thing to ever happen to mobile browsers. Without it, I would never use my phone for browsing. Every other browser can optimize until the cows come home, the typical web bloat is still going to grind them to a halt.