Always search for the specific ROM thread for "Infinix Zero X Neo (X6811)" on XDA Developers. Do not use ROMs intended for the vanilla Zero X or Zero 5G—the panel drivers are different, and you will bootloop.
In TWRP, go to Wipe > Advanced Wipe and select Data, System, Cache, and Dalvik. Install: Transfer the ROM .zip file to your phone.
Formatting existing system data to ensure a clean environment for the new operating system.
Upgrade to newer Android versions long after Infinix stops providing official updates.
is available for flashing using SP Flash Tool or similar software.
If the phone keeps restarting, re-flash the ROM and ensure you did a full wipe/factory reset in TWRP.