I’m not said student, found this /r/Mastodon. Sharing here since I think it would be good supporting research on this. Shortened description from the info page:

This project is part of a Master Thesis that aims to explore the factors that influence user activity on Mastodon and their role in sustaining decentralized networks. … Ultimately, this research seeks to contribute to the future development of decentralized social networks by identifying key factors that support user activity, offering valuable insights for administrators and moderators in maintaining active and sustainable communities.

Survey link

EDIT: survey seems to have ended