He wants both. But the Qunari leadership has devised a mission to test where his loyalty truly lies. And they do it by placing him against the wall.
He's proven his loyalty to the Qun over the years. He sends his Ben-Hassrath reports. He never breaks any Qunari law.
However, back at Par Vollen, they have their spies watching him in the South. They know he's adopted a name for himself. They know he's recruited mercenaries, a Tevinter amongst them. They see a Qunari settling to a new lifestyle and occasionally bending one principle or another along the way.
He's been abroad for years. The Qun is a distant reality to him now. So what do they do?
They ask him to do what he was meant to do one day: help establish an alliance between the Inquisition and the Qunari.
They know the cost might be his new lifestyle as the Iron Bull, but they don't care. This is a demand of the Qun. If Bull fails, he's declared Tal-Vashoth. And to make sure he obeys, they send the elven Qunari to spy on him and report what was Bull's decision: to save the alliance and fulfill the demand or betray the one and only true mission he had ever since he was ordered to join the Inquisition and be branded a traitor.