After more gameplay, for seated position, colour tracking with ROI for everything is still the best option.
For some reason, skeleton tracking for seated position gets worse with time. After a long while, it’s more shaky than colour tracking HMD.
The only problems left are the minor jitter for colour tracking and sometime crashing/glitches because CPU utilization is maxed out.
It’s definately playable for long duration with colour tracking for now!