An Apple account is required in many situations (e.g. you want to download something from the Mac Store, you want Find My Mac etc.), but Apple doesn't cleanly support multiple accounts on any of their devices (and they probably have no incentives to do so)
It's also a PITA to have single devices with single accounts. For instance 2FA is a pain, you also can't use features like sidecar.
All in all, Apple is really bad at this and makes you jump through hoops if you intend to have clean separation between your work and personal accounts.