Journal App entries missing photo and video media after transferring to new iPhone

I transferred my Journal App data from my iPhone 13 to my new 16 Pro, and all the entries made it over, but any media that went with them appears as greyed out icons. After deleting and re-installing the app and transferring everything again, it didn't work, so I'm not sure how to fix this.

I still have my old phone with the unaffected entries if there's anything I can try doing with it.