Though really I’m skeptical that much corporate info is secret for competitive or privacy reasons.
Mostly it seems to be for liability / discovery reasons. Which are still legit of course, but ideas are a dime a dozen and every company has more than they know what to do with. It’s the resourcing and execution that are hard.
After the massive copyright infringements and recent "who care's about the law anyway" stance of corporate America, trusting this could be a grand mistake.
Just treat it like a contract worker. They may violate their NDA. That doesn’t mean you never use any for any purpose ever. It’s a risk that’s been managed since before computers.