But in reality, he wasn't too disappointed.
Negotiations may have broken down, but as long as there's room to talk, it means there's hope on the horizon.
The bottom line Gu Hang can accept is that the Alliance Army can go beyond borders to fight for the Empire. However, the conditions should be the same as any Star Realm Army Corps conscripted by the Empire, with the Empire paying the war expenses and granting rewards. The Alliance can handle the logistics, but everything must be paid for.
Moreover, the Alliance Army must have complete autonomy in operations. They can accept assignments from higher command in joint operations, but the operational command must be decided by themselves. And if the battle is primarily led by them, then all other Imperial military units must follow the Alliance Army's command.
If this condition cannot be agreed upon, there's no need to talk further.
And once agreed, in Gu Hang's view, it's akin to securing the High Lord position at no cost.