Under the leadership of Holy Terra, they might have opened up communication and navigation between the surrounding Sun Star Domain and even the Sun Zhou Domain. However, as the area under Terra government's control grew larger, they not only failed to gain more strength, but instead acquired more burdens.
This stark contrast is like the Dark Side Expedition.
The more the Dark Side Expedition fights, the larger it becomes. Every captured location, with slight development, becomes a supply source rather than a burden in most cases. In rare unfortunate cases, it doesn't affect the overall situation. In such circumstances, naturally, the more they fight, the more it flourishes.
But for Holy Terra re-expanding the Empire's scale, perhaps at first, it could rely on the immense wealth accumulated in Terra to support it; but if most newly captured worlds are a burden, even Holy Terra cannot bear such a load.
