Maybe your location is unfortunately very much interfered from clouded connections and therefore your connection quality becomes bad despite of good signal strength. For such case not only your phone but the other might have the same problem. If you see better performance on the other brand phone then you better inform Samsung SVC as they usually react very fast for such issue. Using one SIM instead two SIMs I don't think it would be solution for your case
No actually i was using Note 7pro i was getting full network & internet works awesome but with A30 & A50 its not working good & even getting single network bar whereas in Note 7pro i was getting full bars at same location
