>When you make changes to the world, the seed is changed to make sure the change you made appears the next time.

Okay stop, this is complete ignorant nonsense. That's not how seeds work. You're proposing some sort of mechanism that could losslessly compress several hundred K of arbitrary data into a single number. Not only is that not how Minecraft works, it's literally impossible.

How Minecraft actually works is that a chunk is generated once when it's initially discovered, then written to disk. Any subsequent changes to that block are written to the save file.