To expand on what Niel said;
An app is forever tied to the Apple Account that acquired it -
An App Store app is forever tied to the Apple Account used to acquire it (paid or free). The Apple Account is encoded into the licensed copy that is downloaded. It is in the copy's DNA. That is the only Apple Account that can redownload or update the app.
The situation you describe can happen if there are apps (or media purchases) on the device that were installed (or downloaded) under a different Apple Account, and they need updating or re-downloading. The best way to resolve this is to delete the item(s) requesting the update and then download it again using the Apple Account signed in with the device. You may have to repurchase the item with your new Apple Account.
M1 Mac mini, macOS 15.2; Watch, series 10 GPS-only, watchOS 11.2; iPhone 16, iOS 18.2; TV 4th Gen, tvOS 18.2; HomePods, audioOS 18.2 and Airport Express w/ Airplay 2