Yes, you MUST release more water from behind the dam BEFORE the surge from upriver from the rains reaches the dam itself - there is always a delay. But once the rain falls, you can only time the delay. You CANNOT stop it!
That said, lake capacity-per-foot-of-height is always slightly greater the higher the lake levels rises because all lake valleys are wider and longer as the lake level rises - that helps. 167 meters to 175 meters is a pretty larger distance, but the spillways should be releasing at their maximum rate now if they are not already. Yes, there will be damage downstream from the higher waters, certainly higher than what was promised when the dam was being “sold” to the country.
Those “promises” of reduced flooding and saved lives downstream were made by the Communist government by its Communist engineers for the glory and power of their Communist leader-dictators. What could possibly have gone wrong - other than the twice-higher-rainfall levels this year?
But global warming was to bring droughts and deserts everywhere, wasn’t it?
“capacity-per-foot-of-height is always slightly greater the higher the lake levels rises because all lake valleys are wider and longer as the lake level rises”
That is a very good point. This is not the water rising in a fixed swimming pool - it is varied terrain. Before reaching 175, or 181 meters, the water might spill over into other areas upstream - maybe huge catchments will have to flood, before the water can get that high.