Apple can completely reset a device if a person can provide sufficient evidence of valid ownership. This is done online at: Activation Lock support request - https://al-support.apple.com/#/additional-support Apple says, "Proof of ownership documentation is required," but does not provide many details in the article as to what is acceptable proof. Prior to this official service Apple typically required the original receipt* issued by Apple or an Apple Authorized Reseller and documented provenance (so typically it would be the first owner who does this, or a descendant with legal proof of ownership transfer).
To avoid this in future, consider:
Apple Business Essentials --> Intro to Apple Business Essentials - Apple Support
Apple Business Essentials includes all the features of Apple Business Manager and more. Apple Business Essentials is one complete subscription that seamlessly brings together device management, 24/7 support, and cloud storage so your small business can easily manage every employee’s iPhone, iPad, Mac, and Apple TV (that your organization owns)—every step of the way. Apple Business Essentials is currently available only in the United States." 20220427