[Q] Hyundai T7S battery hdmi speaker issues / problems

Hi,

Have the tablet with cleanrom via slatedroid, rooted.

Issues -

1. Battery drains in less than one hour. Simply browsing the web, no video or gaming.
2. HDMI connected to Samsung TV leads only to no signal, fiddling with hdmi zoom and aspect ratio has no effect.
3. speaker on the device is always on with white noise.

Been searching since I got it, two weeks, would really appreciate any hints on any of these.

Cheers