People treat Mozilla and Firefox as the sole defenders and saviors of browser space from the evil monolith Google. This is an image mozilla enjoys quite a lot, especially if you read their manifesto, which includes statements like “The internet is a global public resource that must remain open and accessible.” (in the face of what?) and “Commercial involvement in the development of the internet brings many benefits; a balance between commercial profit and public benefit is critical.” (Hmm, who is Mozilla referring to putting commercial profits first?). Despite this manifesto, Mozilla does things like, make Google the default search engine because Google pays them, and bolting on telemetry/adware for 1% of German users without their consent as a “small experiment” to improve “privacy”. For Firefox to not be spyware (aka, to not dial home on startup, not DoH to cloudflare, not use glean, and opt-out telemetry you can’t easily disable, etc) and adware (pocket, “top sites”, extension ads), users need to either do a lot of config editing (in which you hope Mozilla doesn’t introduce new telemetry between updates), or use forks like Librewolf instead of using browser projects that actually respect your privacy like the qtweb{kit,engine} browsers (falkon, qutebrowser), gtkwebkit browsers (badwolf, luakit), and SerenityOS’s ladybird browser; which are also fully open source and don’t feed Mozilla and Google’s “duopoly” (monopoly).

B-but how do I use extensions with web{kit,engine}???

If you just need adblocking, get a hosts list, or run a local dns server like unwind or unbound that doesn’t resolve domains on your blocklist. This has the added benefit of adblock working even outside of your browser. Here’s the one I use. If you need something more …sophisticated like 7TV/bTTV twitch emotes, userscripts from Greasyfork have you covered.

DNS blocking doesn’t save me from Youtube ads

Again, userscripts can help with this, but you should really install a good 3rd party youtube client like the excellent pipe-viewer.

That doesn’t save me from annoying scripts and paywalls

This is a harder problem to solve, but your browser may allow you to create a simple toggle for scripts, here’s configuration for qutebrowser that lets you add a keybind to toggle scripts on and off for a specific domain and save it your config: 'some keybind': 'config-cycle -p -u *://{url:host}/* content.javascript.enabled ;; reload'. It’s no uMatrix, but it’s a start.