Thank you for using the Apple Support Communities! I understand you'd like to know if you can use your work iPad as a second display for your Mac with Sidecar. I am happy to answer this question. It sounds like your work iPad is signed in using a different account than your Mac, based on your description.
For the most part, Sidecar just works. You just ensure that both your iPad and Mac are signed in to the same iCloud account and are on the same local wireless network (or connected with a cable). To get started with Sidecar, you just select your iPad from the AirPlay menu in the menu bar of your Mac. Sidecar support is included at the system 8JyH.