What is the ruling on delaying ghusl after a wet dream until sunrise due to the difficulty of performing ghusl at dawn?

The majority of scholars agree that whoever wakes up and is required to perform ghusl (ritual bath), and the time for prayer is short, making it impossible to perform both ghusl and prayer within the time, must perform ghusl even if the prayer time expires.

Therefore, you are obligated to exert your effort in performing ghusl and prayer at the beginning of its time. If the time expires and you are unable to purify yourself until after its expiration, there is no blame upon you, as Allah Almighty says: "So fear Allah as much as you are able."