Find the name of a fantasy novel

The main character and his master had been practicing in a formation for 800 years. Originally, his master could have ascended to the immortal world long ago. His master wanted to wait for him to ascend to the immortal world together, but the main character couldn't ascend when he passed his tribulation. Later, he learned that the Heaven Realm had helped him postpone it by 3 years. The reason was that the cultivation world was lagging behind and asked him to help the cultivator. That's all I remember. Who knows the title Another point is which array is 8000 years old and only 800 years outside It's a modern cultivation technique