I remember way back, around 2013, asking Gigabyte Mobile for the kernel source of one of their devices (Mika M3) via their business support.
Needless to say, they obliged! They uploaded it and then gave a link to an FTP server and credentials to use it.
So sometimes it’s just worth asking.
I couldn’t compile it fwiw, because it was missing key Mediatek components, but eh, what can you do…
I shall yoink that, thank you very much.