Because it’s not the same object, when using Cell Fracture as you probably have noticed, multiple objects are created that together fit the selected object, so no matter what was the UV unwrapping of the initial object, now every shard has its own.
To resolve that I would try joining all the shards together, selecting the external faces, going to front/side view and UV unwrapping them with “project from view (bounds)” and then separating the shards again. This should work, let us know!
I get an error when joining the blocks for some reason. But my main concern is I copied a youtuber who used cell fracture on that exact same block. But for some reason he got a different result do you know why? I tried adding rigid body physics and playing around with e settings but I can’t get it