please share more QoS stats. The problem is too vague.
Yes, you can reset the whole BTS or just the combiner. But the combiner has nothing to do with RxQual (theoretically). I would rather suggest that the TRX may have a problem.
But anyway, you really need to describe your problem with QoS stats. Right now, I don’t understand your problem : UL QUAL % = 6% is good. CALL DROP % = 0.7% is good.