Use Kialo.edu conversations for large online discussions. For the interactions, students can use their Google account to join, and make up an individual username that they can use.
It's a great setting to include discussion that will authorise your name as your address, can tweak the controls, eg I would have the names on display to see who is who!
The teacher comes up with a useful discussions and the students who are all posting and discussing, fabulous!
Click on Share at the top right corner, then Invite.
In Invites & Permissions, give discussions access link
Click on General on the tab to the left, scroll down to Discussion Options so students can see others names
G5 Class example:
https://www.kialo-edu.com/p/04b34949-5fda-4fa7-8510-4a32ab3efd04/71085