Download iPhone apps with new appleID
How can I download apps on iPhone when I previously downloaded them with old appleID?
Depending on your circumstances, and as a possible “workaround” …
… you might be able to form a Family of your current and “old” AppleIDs.
Purchased content might then be shared between your two AppleIDs.
Obviously this adds significant complexity; only you can decide if it’s worth it.
See:
Set up Family Sharing - Apple Support