how to manage dns after migrating on-prem to azuread

have moved all fileshares to sharepoint, app is running on cloud server, users are authenticating to Entra/M365, pc's are all azure joined..

How do we manage on-prem dns? The ask is so that users can vpn in and connect to their desktop PC by name. We can use the firewall as dns, but it won't allow the pc's to dynamically update.. Is there a simple solution here?