I think the answer to all of this is that Google did not see Google Domains as part of the GCP umbrella. Unlike AWS Route 53, it had its on website separate from GCP. What that website did do was sell and bill Google Workspace.
SquareSpace is a reseller of Google Workspace (for people who use SquareSpace for their company homepage), and will not only be taking over the domains, but for those who bought Workspace within Domains, they will become their new reseller.
SquareSpace is a reseller of Google Workspace (for people who use SquareSpace for their company homepage), and will not only be taking over the domains, but for those who bought Workspace within Domains, they will become their new reseller.