Many competitive players use the Digimon TCG mods on Tabletop Simulator. It isn't automated (you have to move pieces yourself), but it is safe and allows for custom cards.
The 1.56 version is significant because it represented a major milestone in the app's development, offering a robust set of features for Digimon enthusiasts:
Step 1: Enable Unknown Sources
Step 2: Download the APK File
Step 3: Download the Data Folder (OBB)
Step 4: Install & Launch
If you uninstall v156, your decks and progress are wiped. There is no account system.