I'm 4.4 GHz now, still no manual changes on Vcore, but I let the Load-Line Calibration on Auto so the real voltage in full load floats between 1.28 and 1.30 V.
I hit 91 C on Lynx.
Again: in real-use full load (playing games, using heavy image/video editing/transcoding) it doesn't get over 55 C...