RPGs are an entertainment media of a sort, and because of that there is the idea that much like with movies, TV shows, and books that if something is getting focus time it should be interesting. That's why regular runs and jobs become grand adventures and the bad guy just happens to be involved at seeming every turn. The thing is, that doesn't have to be the case - especially in more open ended games where tasks can repeat - and in fact, it shouldn't always be the case. Today I want to talk the missions your PCs are running, and how you want to mix them up.
Dystopia = Resource Fetch Quest
One of the games I'm in has become dystopia-esque in a way. One of the things about building settlements in dystopia-esque scenarios is there is a lot of resource management and acquisition that has to happen. You have to get food. You have to get water. You have to get medical supplies. Anything you want for your settlement probably needs to be acquired, and that means fetch quests.
The thing is, recently one of the player requested "anything but a fetch quest." They didn't mind if the fetch happened, they just didn't want it to be the focus. A fair request in my opinion for reasons we'll get to later.
In my Star Wars game I had a similar thing happen. The PCs, being a highly effective unit, were used for several missions in succession that boiled down to "we need you to get these important people out of Imperial hands." After a bit one of the players pushed for a much more dangerous mission - one they'd have less to do in - just to avoid yet another mission where it was about rescuing people.
In both cases the problem wasn't the type of mission. It was how much it had been done, and in particular how many times it had happened in what felt like a row.
RPGs Don't Have Montages
Staying with the problem side of things, one of the reasons you get fatigue towards a mission boils down to the fact that RPGs don't have montages. In a movie you would get a montage showing the team being highly successful and rescuing multiple people - or acquiring things their settlement needed. It wouldn't take several full sessions of game, but more like 2-5 minutes with a catchy song going on.
In an RPG though each of those jobs has to be played through. The PCs have to plan them, execute them, and bring them back home. To add to that, in order to have entertaining sessions the GM feels obligated to provide challenges. Things that go wrong. Combats. Puzzles. Little nuisances or out of order data.
A mission on its own this isn't a problem, it's actually a good way to do it. But pile it on time after time and it adds up quick, and it gets draining. Worse, it gets boring too. I mean, how many times can you break into a high security prison, extract VIPs, and get out before it's ho hum regardless of the challenges the GM adds? How many times can you head into the wasteland for parts X, Y, and Z before it's just blah? That depends on the player, but it's a finite number.
The Solution? It's the same for both.
Variety Is The Spice Of Life
Like I said, the answer to both is variety.
Mix up your mission types. Don't just have them be endless fetch quests. Throw in other things. Recruitment missions, meeting new settlements, fending off attackers, attacking other places. Whatever it is, mix in other things and try to keep from repeating types as hard as you can. It will happen, but try to limit it.
Second, don't feel obligated to have every mission be worthy of a movie main conflict. Sometimes things go wrong, but sometimes things should go according to plan - especially if the PCs have done the thing before or are otherwise professionals at the task. For example, in Shadowrun, sometimes a milk run should be a milk run that goes according to plan.
There's a good reason for having some tasks just be smooth sailing too by the way. Everytime you show that your players can have things be smooth and just go according to plan, you reaffirm that it's possible. Everytime that something doesn't interfere from left field you show you'll play things straight. This means that when you do mix things up it will be more impactful.
So throw different objectives at your PCs, don't feel the need to spice up every job the PCs do. Save the energy for the times when it does go weird, and make those even more memorable.
Your game will thank you for it. Especially when they get used to things going smooth and get blasted by things suddenly going pear-shaped.