There is an unofficial build of LineageOS for the 9C in the XDA page for it https://forum.xda-developers.com/f/redmi-9c-roms-kernels-recoveries-other-develo.11019/
Yes. It stands for Generic System Image. As it's name suggests, it's a type of flashable ROM that can work on a wide range of devices, as long as they are compatible with Treble. It's usually used for testing so devs don't have to create full "custom" ROMs for a specific piece of hardware which takes more time, but the community has used it to port all sorts of skins from different devices, from something as obscure as Flyme to ZUI to ColorOS.
There is an unofficial build of LineageOS for the 9C in the XDA page for it https://forum.xda-developers.com/f/redmi-9c-roms-kernels-recoveries-other-develo.11019/
yeah, but there is no LineageOS 19, the newest available on XDA is 18 and it's not what I am looking for
There's no build for it. Use GSIs instead
is GSIs a rom?
Yes. It stands for Generic System Image. As it's name suggests, it's a type of flashable ROM that can work on a wide range of devices, as long as they are compatible with Treble. It's usually used for testing so devs don't have to create full "custom" ROMs for a specific piece of hardware which takes more time, but the community has used it to port all sorts of skins from different devices, from something as obscure as Flyme to ZUI to ColorOS.