In the past, the solution for this type of need would be to set up The Littlest JupyterHub as it easily handles this number of connections and doesn’t require Kubernetes. But I am unsure on how well it works at present? Maybe someone could comment on that?
I’ll point out that the most active discussion around MyBinder that I see is via the Zulip resource.
See https://jupyter.zulipchat.com/ about ‘Jupyterhub’ / ‘Hetzner’.
The Community Calendar of Meetings is also a good way to find appropriate meetings so that you can connect with community members. See here and here.