FYI - I recently upgraded from an IPad Pro M1 to the new M5 and it carried over both Playbeat 4 and Soundbox during the transfer and of the installed packs, but I encountered numerous errors when attempting to load presets in each afterwards. All of the packs on Playbeat 4 were located on internal storage, and for Soundbox it was on external storage. Removing and re-adding the packs without reinstalling worked temporarily but then broke again.
As far as the packs, Playbeat had some add-on packs from Audiomodern, and a couple user packs that I created myself, and the same for Soundbox, except for one third party pack, I believe, so there was nothing particularly unusual about my setup, imo.
So far, after reinstalling the apps and reinstalling and re-importing the packs, everything seems to be working. I took several screenshots of the errors I observed if that would be of interest.
