To minimize risks:

: Game developers (GAMEVIL) often patch currency tricks and monitor for anomalous stats, leading to permanent account locks. Unstable Versions

Searching for a mod with 9999 Zen is common because the original game is heavily designed around "freemium" mechanics that often require massive grinding or in-app purchases to stay competitive. Using a modded version can significantly change the experience, but it comes with distinct trade-offs. Why Players Look for the 9999 Zen Mod

If you are looking for a reliable setup, here is what typically makes a "good" mod post or version: What to Look For in a Mod

Some versions attempt to remove the persistent internet connection requirement.