You can set up a second ID for Messages and Facetime. Sign into a different Apple ID for these services in Settings. Note this has to be the same ID for both. Go to Settings > Messages > Send & Receive, and make sure both your telephone number and Apple ID are input there and both show a checkmark. If you need more help, check this link: Add or remove your phone number in Messages or FaceTime - Apple Support .
You can also set up the other phone with a different ID and keep your two personas separate. You should only do this though if you really wish to keep everything separate. In a work context it may make sense to do that anyway if you have two devices.
If you already have your personal ID on the work phoen, if you sign out of the work phone with your personal ID and sign in with a work ID you will be given the one-time opportunity to keep data in various categories. If you select a group then this will be merged with the ID you are signing in on. So if you have a mixture of work and personal contacts on your current account signed into the work phone with your personal account, it may make sense to retain those and let them merge with your new work ID. Then delete the ones that are not work related.
