Additional team and channel-related features and issues within Microsoft Teams for Education
Hello Jack G! My name is Jeremy and I’m happy to help you with your question.
There is not currently any option to remove the Subject line in a Teams post.
I would recommend sending feedback directly through the application.
Here is a link on how to send feedback directly to the development team about possible future options or QOL changes.
https://support.microsoft.com/help/c0fb6297-22af-4db5-b19b-69e0a6720927
Regards,