It seems Theory A is the problem. DNB really need to speed up rolling out their indoors 5G DAS. I'm not sure what building that have indoor 5G DAS in Malaysia currently because I never seen one.

And based on your experience, all that UE in peak time is really choking on that one base station which prove to be to much to handle.
Note:
I heard that the goverment parliament building have 5G DAS but I can't verify it myself.