If you enjoy tech projects and manage to successfully unlock your Nokia C100's bootloader via community exploits, flashing a lightweight custom ROM or AOSP GSI will absolutely make the device better. It strips away carrier clutter, frees up vital RAM, and gives you complete control over your hardware.
Discovering the currently available online nokia c100 custom rom better
A factory reset within recovery clears out old system code to prevent software conflicts. If you enjoy tech projects and manage to
: Reboot your phone. The first boot can take up to 15 minutes. Once booted, go through the setup process and enjoy your "new" device! frees up vital RAM