Giving the player agency whilst also restricting them?

So I'm planning to make a fallout 4 quest mod sequel to a previous mod of mine. The idea is the player gets enslaved for a financial failure due in part of the players previous actions, they're taken to a coastal town and thrown in the slave district, explosive collar and all. Here they meet a friendly old man slave who wants to help them escape (and incite a slave rebellion), but they have to increase their rep to get more prilges. Now the idea is you would do about five short quests, with only three needed to be done, and can accomplish in multiple ways. Combat would be relatively light since slaves killing one another or guards results in a missing head.

As they reach act 2 things would branch up more while still having the collar restrict the player. Instead of simply doing a slave rebellion you could also get some of the guards to mutnity as well..in exchange for some power in planned new order, or even get the help of a cannibalistic cult. In exchange for..maybe a few of the weaker slaves.

The full idea is that this town would eventfully be a sorta hub for future smaller quest mods but I need a way to have it so that the old man slave lives no matter what, the player feels like their actions do matter somewhat. And it's doesn't feel like a endless slog of dialog.