Got an email from them about some domains. They say it won’t happen for “at least a month” as the transaction closes and migration begins. They also said:

Squarespace has publicly committed to continue to utilize Google Cloud DNS infrastructure, meaning reliability and performance regarding DNS will remain unchanged during the migration. The purchase is currently subject to regulatory approval and other customary closing conditions. Upon the closing of the transaction, your domain account will be owned by Squarespace but you will continue to manage your domain(s) via Google Domains as you do today, with Google’s Privacy Policy and Terms of Service continuing to apply.