You cannot flash these ROMs like a normal phone. The Nokia 3 requires a :
If the ROM doesn't include Google apps (Play Store, etc.), flash a GApps package immediately after the ROM.
Because the phone has modest hardware (Snapdragon 429 and 2GB/3GB RAM), developers focus on "Lightweight" and "De-bloated" experiences. The gold standard for stability. Strips away all background telemetry.
The "Nokia 32 Exclusive Custom ROM" is the most exciting thing to happen to low-end Android since the Snapdragon 800. Just don't expect Nokia to thank the developer for it.
But a storm is brewing in the shadows of the XDA Forums. A developer known only as has done the unthinkable: leaked screenshots of a fully functional, stable, and exclusive custom ROM for the Nokia 32.
Practical Steps for Building and Releasing an Exclusive ROM