Before making the decision to "graduate," Flash must have certainly understood what he would have to bear and face from then on.
Doing so was undoubtedly making an enemy out of the entire Ninja Village organization and the forces behind it.
Therefore, he is intrinsically a character with immense resolve.
After leaving the Ninja Village, his investigation into the background of the entire organization has been ongoing. By societal standards, he has made a considerable contribution. (Of course, he might have just wanted to do it for himself, as this is closely tied to his own past. The world did not treat him, an abandoned orphan, kindly, so naturally, he is under no obligation to give back to it.)
Flash has not only resolve, but also a sense of mission.
From the moment his ideas began to diverge from Sonic's in the Ninja Village, up until the actual execution of his "graduation," the effort he put in behind the scenes, along with the pressure and pain he endured, are definitely beyond our imagination. In the old version of God's illusion, Flash mentioned: "Sonic, I feel like I just had a terrible nightmare." I believe that, experientially speaking, the pressure and suffering Flash endured in the Ninja Village were absolutely far greater compared to Sonic, who was a native of the village. That is exactly why the illusion of building a new ninja village together with Sonic appeared. It's not necessarily that he wanted to realize this dream so badly. After all, Flash had been working hard behind the scenes on his own plan for a long time (as mentioned in the dialogue). Rather, for the Flash who was trapped in the Ninja Village at that time, before he had finalized and achieved his own ultimate goal, the blueprint of building a village with Sonic was the only thing that allowed him to hold onto hope. Flash's mental endurance was indeed a bit weaker when it came to the hellish environment of the Ninja Village. Of course, the latest canon version removed this unnecessarily melodramatic plot point, so you can just toss this setting into the trash can.
Honestly, I admire Flash immensely. This is, without a doubt, a very perfect and independent character. It would be great if there could be more depictions of his story outside of the Ninja Village arc.
It's a pity that Flash's screen time is truly too little. The character's popularity is too low, and not many people truly like him for who he is. It is a great shame.