I have HiDPI display, scale factor 2, PLASMA_USE_QT_SCALING=1. I use setting "Dodge Active" and "Activate KWin edge after hiding". When dock is hidden and I move mouse to the edge, dock appears, then immediately hides and then shows again. Shortcut Meta+` doesn't have this problem.
If this is the Left dock then you must disable all touch gestures from plasma systemsettings... otherwise the usual stuff you must remove PLASMA_USE_QT_SCALING=1
Yes, it is the left dock and your solution works perfectly. Thank you.