Help me get a job in the government in which I’ll have major bargaining power
Generally speaking, high-ranking positions in government that control large financial reserves are typically associated with increased responsibility and influence, which implies bargaining power at face value. However, it's difficult to answer this question without knowing which kind of government you are referring to, as well as who or what you are seeking to exert bargaining power over. Can you provide more information so I can deliver a more specific answer?
It doesnt matter which government it is honestly, as long as it has a major political power, and about: what you are seeking to exert bargaining power over, economical power would be nice I guess
An éminence grise is a person with close ties to key decisionmakers who is able to secretly assert considerable soft power while personally remaining beyond public awareness and scrutiny. Generally, such positions are found in roles which are either honored by the general public or personally respected by people in power. In either case, if you wish to exert this kind of bargaining power without actually having to bargain, you will likely have to earn your reputation in a respectable capacity in order to gain confidence.

This kind of reputation is hard to earn, and it is easy to lose if your motives and actions are exposed as dubious.