I don't quite understand what is in the current 15th January version, because the earlier changelogs are not in the second post anymore. What is/was fixed in the Oct/Nov builds.
OP spoke in december about Dual 4G/VoLTE, and other things like G-wallpaper app (useless to implement if it's also freely available in apkmirror/play store, why should you bloat the ROM). Could OP add all the changelogs to the second post? And known bugs in the OP, such as the Fingerprint scanner are still known bugs, as a separate bugfix is necessary in some builds. Another thing for me is I'm unsure if the IR blaster works, same for FM radio.
Anyway, good job maintaining and working on this build, and good luck with your exams. Experimental Android Pie/9/16 couldn't bother me as much, as I would rather prefer a stable build over multiple crashes/restarts/voice/camera/etc bugs, so this work appreciated! The clarity of the posts by OP could be improved though.