In situations where you have important information that you need to share without blatant exposition, it can be helpful to start by hinting toward them and letting the audience come to understand what's going on a little bit more and more over time. Don't be afraid of letting it take a minute for the audience to fully grasp what's going on, as long as you keep them intrigued. Hinting toward what's going on can actually be really fun too, teasing the readers a little bit and keeping them hooked so they want to know what happens next.
Example: you said there's a rebellion going on, perhaps have a character mention to someone that they should stay out of a specific area of the city because there have been some signs of rebel activity going on there, and the last thing they need is to be caught in the crossfire. You don't have to immediately say what the rebellion is about, or who the rebels are immediately.
Similarly, you said there's a massive dome encasing the city, perhaps hint toward the absence of light in the empire.
Things like this can really help you, remember, that foreshadowing is your friend, and so is having people speak about situations as if the people they are talking to already know what's going on. it avoids the awkwardness of blatant exposition (especially if everyone already knows what's going on) and works similarly to foreshadowing by giving readers a bit of information about what's going on, but not all the details, which the characters know that "everyone" already knows.
An example from my own story. My character Kattar is rehospitalized, but neither the reader's, nor the MC, Alicia,his best friend was informed. I inform the readers of this by having Kattar's mother call Alicia asking her if she can take Kattar his hospital bag, as she's out of town and hasn't been able to change her ticket. She speaks to Alicia as if she knows that Kattar in the hospital, because she assumes he would have told her, and this allows the readers to slowly come to the realization along with Alicia of what exactly just happened.
(“‘Licia, dear, I’m so sorry to add more to your plate when you have such a busy schedule right now but I haven’t been able to change my ticket yet - and the airline is giving me a lot of trouble-” she sounds like she’s on the verge of tears “So if you could get to Kattar today or tomorrow and take him his bag - he already had it packed with anything he might want, it’s in his closet in the left corner. He wants it before Friday and I don’t think I’ll be able to get back until Saturday morning at the earliest. I would really appreciate it-”
I’m dumbfounded trying to process what she saying as she continues on, talking and apologizing until I finally find my voice.
“Mrs. Moon, where is Kattar?”
“Oh, room, 4A on the fourth floor, the same one as last time. I’m sure a nurse can show you but…”
And that’s when the shadow hits me.
I’ve never broken down that fast.)
Hope that helps!
