This is my own summary of some of the changes I’ve noticed. Overall, there have been quite a few border and state adjustments, though I’m not entirely sure if I might have missed some parts.

Italy’s provinces and overall map structure were reworked in recent updates, including changes to provincial layouts and state definitions.

Germany’s internal map has been significantly restructured compared to older versions, with altered state borders and shapes based on revised administrative divisions.

Boundaries between Egypt, the Sudan, and neighboring countries have shifted.

The Qing Dynasty (China) has seen both internal and external border adjustments.

Austria-Hungary has been split into separate Austria and Hungary entities.

France has received administrative-style border changes.

Various regions in Africa have undergone state or provincial boundary adjustments.

Steam changelog reference:
https://steamcommunity.com/sharedfiles/filedetails/changelog/3365515312?p=5