I am trying to identify inactive Teams, I work for a reasonably sized company so we have hundreds of Teams setup. I have tried running a Usage Report but that only shows Teams that have had activity within the last 7, 28 or 90 days, if a Team has had no activity for over 90 days it does not seem to appear within the report.
Also, I want to know the space they are consuming.
Generally, the reporting functionality (M365 Admin Center, Microsoft Graph) allows you to go back 1 day, 7 days, 30 days, 90 days or 180 days. If you require additional reporting over a longer period, you would probably have to start storing these details in a separate database so you can do more reporting on them.