Rebirth: Future Phone in the City

The protagonist Lin Bei, poor and dead at 35 in 2024, is reborn back to 2015 at age 22, obtaining a future phone from 2044 (V2.44 system upgraded to V3.0) with 5 major apps (Social Prophet, Real Estate Radar, Script Library, Hit Music Library, Medical Data), limited to 3 uses per day. Starting as a car mechanic, he rises to become a business empire builder. — Description from novelcodex.org