That is what a support team is for.
And those access elevations will be tracked and audited, just like at any other organization that handles sensitive data.
This isn't some super duper secret, when shit breaks there needs to be a, well secured, escape hatch for the people who fix things to crawl in and make repairs.
Prior to cloud hosting, Microsoft could get permissions to remote in to your servers, or prior to those days, send someone physically out with a laptop and a debugger.