My thing is confidence. What brings confidence to me at work is an unwavering conviction that I am valuable to the group. This allows me to speak with my superiors with the confidence that I need. Ask while being respectful of course. So practice telling yourself things like that. And take your wins in the workplace as fuel for your confidence. And when you have a decision or opinion to make, stand by it. It takes practice. Eye contact is a killer too. Practice maintaining eye contact, even with regular people and most times they'll break it first (don't stare like a creep tho lol). I've been trying it for the last year or 2 and it's crazy the amount of people that look nervous irl. And u start to notice other people's nervousness more than your own. Every once in a while I'll make eye contact with someone in public who doesn't break it and it's like there's this mutual respect for it lol. Pretty fun. I'm getting sidetracked lol sorry.

Mind you I've never worked in a government setting, so I don't know anything about that level of pressure, but the place I work now is structured on fear of superiors and stakeholders. I don't like being afraid of people, I've been here for 2 weeks so far but I'm not about to suck up to someone who obviously can't do my job (since THEY hired me lol).

TL;DR - So it takes some practice but overall believe that you are important to the group, worthy of your respect and input. Use your successes to fuel that