Why post on an Android Oreo thread then?
There's no Android images publicly available for the Pi 4.
I think you already got your answer elsewhere. This was also recently discussed here (https://forum.xda-developers.com/showpo ... stcount=19).
Good luck. It looks like it's not going to be too easy either.
https://www.raspberrypi.org/forums/view ... 7829df1de2
LineageOS 14.1 doesn't support Pi 3 B+, though.