Hi,
You might want to check the meeting policies for Microsoft Teams:
Manage meeting settings in Microsoft Teams
https://learn.microsoft.com/en-gb/MicrosoftTeams/meeting-settings-in-teams
Also something here might help:
Creating, attending, and running meetings while using Teams for distance learning
https://support.microsoft.com/en-us/office/creating-attending-and-running-meetings-while-using-teams-for-distance-learning-788d730f-2c7e-4761-a059-c9b3fe87adf7
Microsoft Teams meetings support up to 250 concurrent attendees:
https://learn.microsoft.com/en-us/microsoftteams/remote-learning-edu#teams-meeting-scenarios
Best regards,
Leon