App Store Updates

Apps, purchased with one Apple ID, will require that you repurchase them if you use another Apple ID.

If you are still only using only one Apple ID (not sure based on what you posted), then the issue may be with the payment method you are using with this ID.

Ref: If you can't download or update apps, or if apps get stuck - Apple Support

Apps are permanently tied to the Apple ID that was used to download/install them.

If you changed your Apple ID, you need to sign out, restart your iphone, sign in with the old Apple ID and update the apps.

or

Use the old Apple ID, delete the apps, restart the iphone, sign in with the new Apple ID and redownload/reinstall those apps (but you might lose the apps related data/documents)

Regards

Giulio