My XP repo has about 2GB (Windows XP German).
You don't need a link to the cumulative updates as wsusou won't download superseded ones. Also the updates will be downloaded only once. If there are new updates, wsusou will just download the new ones and delete the superseded ones. wsusou will reject or ignore manually added updates, depending on your configuration, so wsusou won't be any faster, if you manually download the updates.
If you want to search for a specific update, take a look at this page:
http://catalog.update.microsoft.com/
Wer Rechtschreibfehler findet, darf sie behalten oder an den Meistbietenden versteigern. / Everybody finding a misspelling is allowed to keep or sell it.
aker
WSUS Offline Update „Community Edition“
https://gitlab.com/wsusoffline/wsusoffline/-/releases