I'm on a "regular" Google Apps account (ie, grandfathered into the old free one aka gmail on a custom domain).

I can use this fine, with some gotchas:

It'll only allow different users on the same gsuite account to connect. I can't, for example, invite a personal gmail account or an account on a different gsuite domain.

We use Google Meet at work for meetings, which also supports "Casting to a meeting", but that requires gsuite as well.

I just tried it and it seems to work even though I don't have an Education account. I don't have any modern Android devices though so I just casted one tab on my laptop to another tab on my laptop.