The LineageOS devs have been working on a device tree and the ROM for a bit, you can see the changes on github. I assume people are waiting for android 10 to be officially released so they can get the kernel source code needed to make the ROM, there is no point making lineage 16.0 (based on android 9) this late when android 10 is in beta phase. So at the moment development has stalled until ASUS releases android 10 and android 10 kernel source.