@Dave Oanzon, Thanks for posting in Q&A.
Could you please confirm us that " your boss wants every employee not to access OneDrive outside the company" means that your boss wants to employees' access OneDrive only in company but no other location. If yes, we can create a conditional access policy with Network restriction. And you can configure the corporate IPs as trusted location and select it in Network session under Conditional Access policy, then only devices can access OneDrive only in the company.
Here is a link you can refer.
Hope it will help.
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