Put your old phone on flight mode first. Just select all photos that you want to have on your new phone, then press share button and enter “Save to files” then go to some folder that’s liked to some app. Make a new folder called “deleted photos” or something and paste the photos there. Now, you can turn off flight mode. And connect your old phone to pc/ mac via cable and copy the “deleted photos” file to your pc/ mac through iTunes > Files App > respective app directory folder > deleted photos folder.

See my last post on r/canon for the answer.