What does it mean when I open a user account in ACP and under the Active Account Integrations on accounts where that is Google, it appears as if it is trying to load something there which spins forever and does not resolve?

Likely this is an error of some kind. Likely with loading the data that is meant to be displayed here, whether that is internal (software/server) or external (Google), with the information provided is unknown.

First step, I would check your browser's develop tools in the console tab to see if there are any errors. If there is a 500 Internal Server Error mentioned there, you will need to obtain the Server Error log entry for that error. If there is another error, please let us know.