choosing 43dBm will not force the MS to emit stronger (they cannot exceed 33dBm, physically), but it will strongly impact your C1 and C2 criterion for reselection.
So keep it at 33dBm.
My solutions below intend to improve the coverage, not reduce it. I didn’t say to downtilt, but “adjust” the tilt. Perhaps you need to uptilt, or perhaps to downtilt, in order to increase the coverage in that area 🙂