JA2 is indeed similar to XCOM in terms of gameplay. If you can live with the very dated graphics, the gameplay still holds up and is even better than XCOM in my opinion. There are some recent mods and patches to fix some bugs and keep the game playable on modern machines.

I’ve actually never played HOI4, the setting just doesn’t appeal to me, maybe it just hits too close to home. In terms of Paradox games I prefer CK3, though that game isn’t without its flaws.