As the initial responder pointed out Google is not an SMS company, so it's not super surprising that they outsourced part of the routing process for conventional sms delivery.
Yes but that third party's DB was accessible on the web. With SMS from mid-2023 in it.
Even if Google wanted to use their services, they still could've insisted on setting up the database, having their engineers remote access to it.
They just signed the contract, did bare minimum, and washed their hands off it instead of taking responsibility of their data.
That's what I meant by outsourcing security.
Edit: The server should've been purging the old data after 14 or 30 days.