Unpopular Opinion: there should be no custom focus trees for Hoi4 to be accurate. What can make Hoi4 so good is that it is an engine, so things work the same for all countries sometimes. Like research, or the combat system. National-specific caveats are understandable in coding a video game. But the point of it all is that the same mechanics for politics and decision making are all in place in each nation, just combining in a way that produces a unique result every time. Aside from that, I would say the first really fun game I had was as Bernie Sanders in Make America Again (An unfortunately dead mod), and maybe also as the Bermontians in Poland.
Edit: A big thanks to Gukpard for making this thread as Hoi4 is a game I really enjoy!
Edit: A big thanks to Gukpard for making this thread as Hoi4 is a game I really enjoy!