All MP4s posted on here are automatically archived to wayback.
They are.
For example this thread.
https://media.128ducks.com/file_store/b42aea0c2553d43d0a4225cf7c469540cd6ed190319263743e58e5339c838a8b.mp4
archived here:
https://web.archive.org/web/20220903201816/https://media.128ducks.com/file_store/b42aea0c2553d43d0a4225cf7c469540cd6ed190319263743e58e5339c838a8b.mp4
Just click on the upmost URL at the left side.
That should be the 128ducks URL, and that should work.
It also works for PDF documents.
And it also works for bigger resolution images.
And it also works for all images when the post was mentioned by baker (notable).
Also works for webm videos too.