If you connected the sheet via Google Sheets Data Ingestion inside Data Studio, HubSpot says updates occur every 5 minutes. You should not need to use Refresh now for normal operation.
The caveat that often makes this look “not updating”:
Even if the external data source is updating, HubSpot reports themselves are not real time.
For example, custom report builder reports refresh automatically every 2 hours, and manual refresh has limits.
So a good test is: check the dataset preview and the external data source status inside Data Studio first, not just the dashboard report.