Same issue here! But I’ll add this… I went back to my iPhone14Pro and looked at apps waiting to be updated, there were about 6 in that list (which is now missing on the new iPhone15Pro). I didn’t update on the old iPhone but looked at the version number, then compared to the version number on the new phone. The new iPhone15Pro did have the updates, so when data and apps were transferred in the update process, sure enough the new iPhone got the latest version. I then went ahead and updated the (old) iPhone14Pro and sure enough, after the updates they were now showing the new versions that were on the 15Pro. So the question is…. Will these apps keep updating now that the initial transfer is finished. I plan to keep track on the iPhone14Pro and when new updates come in, check whether they are updated on the 15Pro.
UPDATE, Issue Resolved… I continued to track the ‘available updates’ and a few hours later an app showed up on the iPhone 14Pro as coming in the next day. I then opened up the iPhone 15Pro and voila it showed the same app as coming up available. The previously missing list was now working… So the reason no updates were showing is that everything had been updated during the transfer to the new iPhone.