Why did God let the world become corrupt again after the flood?

The Flood was supposed to be a hard reset because the world had become completely corrupt and violent. But if God wiped everyone out to start fresh, why did everything fall apart again so quickly afterward? Why not use that moment to permanently restore the world like what Revelation says will eventually happen in the future?

And if that wasn’t yet the plan, why not at least give Noah a better moral framework from the beginning something that could’ve prevented issues like slavery? Especially since some Christians argue God couldn't outlaw slavery outright because it was too embedded in the culture but right after the Flood, there was no culture yet. Wouldn’t that have been the perfect time to set things right?