I think someone on a different comment shared a guide for what you need to do for family sharing which is the best bet. But your Apple ID account is not locked to your phone number. You can be authenticated on multiple devices (phones, tablets, watch, computers, AppleTV) you would go into the settings and then the accounts and sign in with the correct Apple ID. You will just need to sign out from what ever ID it was running from before.

The phone isn’t the issue. It’s the account. You can transfer Apple accounts between phones and even run one account on multiple devices. And redownload the application. Or even restore from a back up of the phone that has them now.

But if you purchased the kids applications on your work account you are probably SOL. Use your own own personal account for personal applications. I would set up the kid with an account and family sharing. You can then be notified of purchases and use parental controls on their devices.