The US was at war during the course of the Manhattan Project. This is not the case now.
Being the sole owner of the first AGI would probably give the US an edge against its peers, but as fair as foreign policy goes, not as much as being the only nuclear-capable country.
For the world as a whole and probably for the US itself, in absolute terms, an entirely open AGI accessible to all countries with the necessary resources could have such an impact in the global economy that everyone ends up better off in aggregate.
It really depends. Locally, factions like criminal associations and retired cops mafias (militias), who always have city councelors and mayors in their pockets, may retaliate if someone with an audience is being too annoying (see Marielle Franco's case).
Nationally, not all politicians enjoy any protection from the supreme court against critiscism, only the best connected ones and the supreme court itself. Recently, a former YouTuber who lost all his social accounts and had to self-exile to the US for some disrespectful comments against the supreme court was sentenced to 1.5 years in jail for calling the newest supreme court judge a "fatty".
Except for the supreme court itself, the average Brazilian can voice their concerns and speak up against corruption with very low chances of repercussions if they don't display wholly anti-democratic discourse, like wishing the military to execute a coup.
Fines are not enough because a large enough fine will kill a company, destroying lots of jobs and supply chains.
Why not dilute the shareholder pool by a serious amount? There's no need for a statization to formally happen, the government can sell the shares back over time without actually exercising control.
Also fire execs and ban them from holding office on publicly traded companies for the foreseeable future.
Seizing shares doesn't impact the cash flow of the company directly, thus shouldn't cause job losses, but shareholders (who should put pressure on executives and the board to act with prudence to avoid these kinds of disasters) are adequately punished.