In a debate, you don’t want ‘questions’ you want statements that support your view.

Points for: Helps build school spirit.

Helps develop character character

Helps your school get well known as it wins games.

Helps you to know what being part of a team means

Points against : Robs you of time that could be spent studying

Can distract the team if disinterested spectators are “watching”

Being “forced” to do things can lead to animosity toward team members.

There is a start, at least. I hope it helps.

Health effects are prominent in both pro and anti sporting questions. Good health from participating, injuries too. Ask about those things.

Team work is an important positive, but you can ask about the pros and cons of individual (non-team) sports, maybe as a means of building more individual self-esteem.

Also I detect that maybe your subject is why students should attend as spectators rather than players. School an team spirit are areas that would provide you with questions, and a culture of inclusiveness. Not all people are athletic, and this might provide a way to include them in the athletic “group”.

Good luck.