I figured out the original issue by clicking within the Catalyst Edit Android app (Backup and/or Save Preset(s)). After doing this, the 'Load Presets' option, which was previously grayed out, became available.
Then to use Presets from Custom Tone:
First, download the Presets you want. If you see an eyeball, turn your phone horizontally and select the Download button.
To access and copy Custom Tone Presets on Android XX, where the default restricted file manager prevents folder access, download FV File Explorer. This file manager grants access to restricted folders such as /Android/Data/*, including Catalyst Backups and Presets. It allows you to copy, move, delete, and manage files easily.
The full path on my Android:
/Android/data/com.line6.catalystedit/files/Line 6 Catalyst/[Backup][Presets]
Updated March 05, 2025