Have u try movie playback? Is in android TV running without issue?
To allow internal BT is necessary to compile kernel, support depends on build-in module. But u can use USB dongle.
Video/Movie playback was ok, actually it's very great.
So I just reinstalled and set up LibreELEC and tvheadend backend again. Now the distorted picture issue almost gone. But still getting sometime.
I think maybe the tuner is prone to get interference easily somehow.
But now it's usable.
Thanks for your build.
Hope this working internal tuner and wifi driver will be merged into kszaq's build soon. 
Edited: Now it seems my distorted picture issue in live tv is completely gone. I'm not sure if this is relevant but I just did enable "power save" and "Low noise amplifier" in web interface and then the problem is gone.