This is the part where we have to put on our lawyer wigs.
Searching for the complete Futurama series on the reveals a mix of fan-uploaded episodes, upscaled collections, and digital extras. While the Archive is a legitimate digital library, the copyright status of these specific video uploads is often contested, and they are frequently subject to removal. Navigating the Archive Content Futurama Complete Series Internet Archive
To make sense of what you find, keep in mind Futurama's complex history: This is the part where we have to put on our lawyer wigs