WotI: Alphatia Lite
by Marc Saindonso if an island-continent would sink, the tidal waves would bring unprecedented tsunamis and tidal waves (and erosion...), and the missing land mass would probably lower the sea level, redrawing shorelines entirely (with Bellisaria and the Isle of Dawn taking much damage). this is not really what happens with the almanach maps.
rather than sinking, there is a "lower level" of mass destruction along the continent of Alphatia, leading some worried Immortals to transport a sizeable bunch of survivors (maybe just half) on a floating island in the Hollow World, altering the memories of low-level people, and creating a landscape that resembles their homeland before it got destroyed (thus the Almanach maps still work for HW Alphatia). For the armies just half the quantity presented in the almanachs.
In the Known World, a ruined but still present Alphatian continent hosts the other half of the survivors experience the equivalent of MCU's Thanos's snap, discovering half their population has vanished. This takes down the Alphatian Empire a peg or two, along with the succession crisis caused by Zandor.
In short, you would get two Alphatias with very similar maps, one in the Known World, another in the Hollow World, but both with halved populations and armies, one with the preserved cities before the war, the other in ruins.
This may compare with the Azcans, with two versions of itself in both settings, one as the Azcan Empire in its glory days, the other as the lesser Tiger Clans of the Atruaghin.
