The stream detector addon often makes it easy to grab the media.
https://addons.mozilla.org/en-US/firefox/addon/hls-stream-detector/

Ah, I take it this is the tactic you use?

Go to https://addons.mozilla.org/firefox/ rather than https://addons.mozilla.org/android/ when you find the extension you want to try use the menu button (hamburger/three stripe icon) and toggle “Desktop site” then you can use the “Add to Firefox” button.

Otherwise, if you followed an extension link, you may have to switch to “Desktop site”, then remove /android from the URL in address bar.

It should then install the add-on, but if it tries to download the file instead, then change privacy.resistFingerprinting.block_mozAddonManager back to the default false in about:config.

Yeah, the main tip was that you can use whatever you use to grab streams from youtube on firefox on your computer and add that addon to a collection to get it on your phone.

Creating an addon collection as per this guide allows me to install computer addons to my Android phone:
https://www.androidpolice.com/install-add-on-extension-mozilla-firefox-android/

The addon I use to grab streams didn’t want to work on youtube though, but it worked to grab video streams from other sites.

Here’s the latest for firefox
https://gitflic.ru/project/magnolia1234/bypass-paywalls-firefox-clean/release/0facfab5-936b-43ab-8b88-be067ee6a81a

You’re downloading the project, not the release
https://gitflic.ru/project/magnolia1234/bpc_uploads

https://addons.mozilla.org/en-US/firefox/addon/hls-stream-detector/ works for most streaming websites

Correct, you need to keep a pristine copy in your torrent folder and make a copy elsewhere.

https://github.com/yt-dlp/yt-dlp