Official Darkness Rises limited your playtime via an "Oil" (energy) system. Once you ran out, you either waited or paid. Private servers universally remove this, allowing you to PvE farm for hours on end.
If you hate the official Darkness Rises , don't try to fix it with a private server. Instead, vote with your feet. Uninstall the Nexon version and find a different game that respects your time, like Punishing: Gray Raven or Genshin Impact (single-player mode). Your phone's security and your personal data are worth more than a few virtual diamonds.
A: Generally, no. Because you are playing on a separate client/app, your official account is safe. However, never try to log into the official Nexon servers using a modded client.
: Check for repositories containing "Darkness Rises Server Files" if you are interested in the technical side of hosting. Platforms like GitHub often host documentation for similar legacy games.