Strategy for moving from Google Workspace

I have the family's email set up in Google Workspace with a custom domain. Four email accounts in total - we will likely need 3 Standard packages and one Premium package.

I cannot figure out what the strategy for conversion should be.

Can I create one account (so, e.g., jesper@mailbox.org) and via that set up additional accounts for the other family members?

Or:

Should I create four different accounts ( so e.g., dad@mailbox.org, mum@mailbox.org, son@mailbox.org and daughter@mailbox.org) and then somehow put them into a family thing afterwards?