He scored 15 goals and 4 assists in 64 Premier League games in the last 2 seasons with Chelsea as a striker/CF. In his first 10 games with Arsenal, he has 1 goal and 1 assist as a midfielder.
I'm sorry to break it to you, but he lacks end product, and his production doesn't justify treating his as a key player on the team. He'll be completely benched in the next few weeks or loaned off in January.
Who ever said Pedri was better than Bellingham?