Survive on a Deserted Island and Become Invincible Once You Leave the Island

The protagonist Shi Chen accidentally traveled to the ancient world, but unfortunately landed on an isolated island. Not only did he have to look for food and water, but he also had to beware of attacks by wild beasts. After he left the island, he discovered that the thousand-year-old dragon in the outside world was not as powerful as a tree on the island. I'm invincible, you can do whatever you want.