I'd say start with Wrath and don't bother with Kingmaker. Wrath is just much more interesting both as a game and as a concept, and there's no shortage of replayability there - the amount of variability between paths is crazy. That said, whichever game you start with, I'd strongly recommend you download a mod to trivialise the management minigame (kingdom management for Kingmaker, crusade management for Wrath). They're a) not fun, b) difficult (and unlike the rest of the game have no difficulty settings), c) have nothing to do with the core RPG gameplay, and d) can brick your campaign if you screw them up.

Also, you know about Baldur's Gate 3, right? It's coming out in two weeks after a very long and successful early access period and it very much looks like all the crazy reactivity of Wrath on a full AA budget.