Came across this article today: https://arstechnica.com/gadgets/2022/01/google-tells-free-g-suite-users-pay-up-or-lose-your-account/

If you are one the old G Suites 50 accounts for free on a custom domain, you might fall under this.

I haven't had any communication from google about my domain, but I think I'd fall under it.  Might take the opportunity to exit google.