Setup:
Download Seal and go to Settings > General. From there click on the update yt-dlp to make sure you're on the latest yt-dlp build. No head to Custom command > New template. Put your label of choice and in the "Command template" section put in your custom command.
To create a good custom command I highly recommend you browse TheFrenchGhosty's Ultimate YouTube-DL Scripts Collection's Watch on Mobile Devices Script to get an idea of what you would want (I'll give an example template later on based on theirs).
Once your command is done click "Done". If you have not configured the output directory yet, go to Settings > Download directory > Custom command directory (Usually you'll want this in the Download folder. On android: /storage/emulated/0/Download/<Name-Of-Your-Choosing> Make sure to have "Configure before download" under Settings > General, enabled. From there, exit the app.
Go to the app you want to download your media from (ie. Browser, Youtube). If you are in a browser, long press the url bar of your link and click "Share". You will be presented a menu to share the selected link. Long press on the Seal icon marked as "Quick Download". You will be presented with a way to pin the app. This will allow this specific app you're in to have Seal be presented right away when you want to share a link and be prompted with the "Configure before download" menu. From there, select "Commands" as "Download type" and click on the template's label you created earlier. You can now click "Download" and enjoy.
You could avoid the hussle of setting up a custom command and tweak a few things in the app's offered options. I just prefer to use my usual commands that I use to download on my phone as well.
As for the command, here's a short template I just made from modifying TheFrenchGhosty's scripts as mentionned above (haven't tested it but should theoritically work):
yt-dlp --format "(bestvideo[vcodec^=avc1][height=1080][fps>30]/bestvideo[vcodec^=avc1][height=1080]/bestvideo[vcodec^=avc1][height=720][fps>30]/bestvideo[vcodec^=avc1][height=720]/bestvideo[vcodec^=avc1][height=480][fps>30]/bestvideo[vcodec^=avc1][height=480]/bestvideo[vcodec^=avc1][height=360][fps>30]/bestvideo[vcodec^=avc1][height=360]/bestvideo[vcodec^=avc1][height=240][fps>30]/bestvideo[vcodec^=avc1][height=240]/bestvideo[vcodec^=avc1][height=144][fps>30]/bestvideo[vcodec^=avc1][height=144]/bestvideo[vcodec^=avc1])+(bestaudio[acodec^=mp4a]/bestaudio)/best" --force-ipv4 --sleep-requests 1 --sleep-interval 5 --max-sleep-interval 30 --ignore-errors --no-continue --no-overwrites --add-metadata --parse-metadata "%(title)s:%(meta_title)s" --parse-metadata "%(uploader)s:%(meta_artist)s" --no-write-description --check-formats --concurrent-fragments 4 --output "%(title)s - %(uploader)s (%(upload_date)s).%(ext)s --merge-output-format "mkv" --throttled-rate 100K
Not all the info here is relevant for each use cases but I hope this gives ideas and helps even a bit.
Okay that's been working SUPER well for me-- Thank you for laying that out. Seriously a game-changer, it's actually better than what I was doing before that stopped working, lol.