iCloud restore : "not enough storage"

Hello everyone 🙂

So i had a problem with my iPhone 6 and Apple send me a new one. So, on my old one, i did an iCloud save, EVERYTHING on my device was send into the 5g storage.

When i did the restore from the iCloud backup, it says on my new iPhone that it can't be completely done because i exceeded the free 5g.

However, how did i exceed it : i did the icloud save, everything fitted in the 5g and now when i want to restore it it says i have too much.

Did this ever happen to you? If so, how can i delete some stuff from my iCloud so i can finish the restore?

Thanks 🙂