I see the last thread on this game that I found is pretty dead. So I'm making this one.
Victoria 2 is the last game of the "old generation" of Paradox games that had fewer, larger DLCs, no mana, and more obtuse yet deeper mechanics. It's, with the
HPM mod and both DLCs, the best and probably most realistic one (but it often does get silly: for example in one of my games the USA went fascist then shattered). It models a lot of things from population (the population is modeled better than Stellaris, fight me) to industralization to elections to rebellions. It is also a lot less "blobby" in that expanding too quickly is hard and often leads to your nation collapsing or getting ganged up on, a bit like a harsher version of EU4's AE. It covers two, in my opinion, interesting time periods: The Victorian Era, and the Interwar Era. The first one sees industralization, Asian/African nations being either conquered or westernizing (as they start out uncivilized. Historically accurate for the time period as they were far behind Europe in technology), and nations like Germany and Italy forming. Then, almost inevitably, a crisis leads to a Great War that, unless one side is very unlucky or it's skewed towards one side, can lead to millions of casualties and extremely high militancy, leading to fascist or communist revolutions, and commie/fascist regimes have unique events and mechanics (a bit like EU4's revolutionary governments I guess). The game ends in 1936.
Do note that the game is unplayable without both DLCs and bland without HPM. The DLCs can be bought at a discount and HPM is literally free. Getting a complete experience is cheap by PDX game standards. I plan to start a let's play someday.