It really is.
I’m in a broadly similar boat to you, and finding the game much stickier with turn-based combat.
Kingmaker’s slavish devotion to tabletop d20 in all its glory means that all the distinctions between move/standard/full-round actions really matter – and that stuff is almost totally elided in the RTwP engine.
All the interactions between feats and combat maneuvers and attacks of opportunity and movement really come out in the turn-based setting they were designed for, whereas it all just kinda mushes together in RTwP and ends up feeling like a low-rent Baldur’s Gate.
BG2 and the IWD games were adapted very intentionally from AD&D to fit the Infinity Engine and be fun, and sanding away some of the nuance of the tabletop system was no doubt very much intentional. P:K adheres to tabletop d20 to a fault, which makes it a vastly better turn-based game than RTwP.
And I’m very much a RTwP guy. BG2 is my favorite RPG of all time, and the IWD games are in the pantheon. But turn-based is just a vastly better experience here.