Puppy acting out

Hello everyone!

My 8 month old whippet has started to act out recently and I am worried it’s because separation anxiety. We have crate trained her since the beginning and we had no problems before. However recently she has DESTROYED her bed, chewed and pulled down curtains from the hangers (through the crate) and she even managed to dent her own crate by pulling it with her teeth. Some days when I come home, she is sleeping peacefully but other times it’s a nightmare.

Has anyone had the same experience with a puppy? What should I do?

For further context: our puppy is usually alone during the morning from one to four hours max. She is super cute and chill when we are home. She is regularly walked and played with.