For those using professional emails w/ Google Workspace.

Every time you want a new domain for email, don't register it as a new GW organization - it will make a mess in your operations. If it's not going to be another company with its own employees, but rather a new dedicated email domain for something, just go to:

Admin Panel > Accounts > Domains > Manage Domains > Add Domain > Use a Domain Alias > Add Domain

And connect your domain as an alias and then set up Gmail filters to keep them separated and organized in your inbox.

It's not even a matter of $$$, because it's only $72/annum paid to Google, but about user experience, as everything is easier to manage in one place without the need to manage two GW organization separately.