How can I use powerful NPCs without overshadowing the player characters?

I’ve been playing P&P for years and have taken my first tentative steps into DM’ing over the last year, mostly leading One-Shots. I am also a passionate world-builder and so I jumped at the chance to use one of my most developed worlds as a home-brew setting. For the most part, this has worked out well and the players like the setting – but I’ve started to notice a trend that’s troubling me.

The setting contains A LOT of NPCs and they range from “average joe” to “movers and shakers of the world” in terms of power and competence. And I find myself somewhat at loss how to handle interactions between the latter and the PCs. On the one hand, those NPCs are meant to be badass, smart and proactive and I want to do them justice. But on the other hand, I don’t want the players to get the feeling that they are being reduced to assistants or – even worse – spectators.

Avoiding them until the PCs are powerful enough to meet them as equals is an option, but I often run into the problem that the “here be cool adventures” and the “here be VIP NPCS” parts of the setting often overlap. So sure, I could send my players to clear out a monster-infested mine or retrieve stolen goods – while the NPCs prevent the brewing civil war, slay the dragon, fight a dead god… all off-screen. Yay?

I have used the “but our hands are tied!”-approach in the past, where powerful NPCs showed up but they were crippled/captured/bound by bureaucracy, which explained why they couldn’t do anything and needed the PCs help. This usually works, but I am afraid of overusing it. It gets kinda weird when characters that are usually competent suddenly can’t do anything every single time the PCs get involved. Plus, it would be rather hard to take them seriously after a while.

And the thing is: I like those NPCs. I spent a lot of time writing them. And I want to use them and I want to play them right and not reduce them to damsel/dudes in distress for the sake of the adventure all the time. (And, I admit it: I want my players to like them.) But the focus should be on the PCs. I want them to be the heroes, to have the spotlight and be awesome. They are the main characters and I want the story to reflect that.

So…. How do I manage that? How can I have a setting filled with powerful NPCs and still let the PCs be the main heroes, while still maintaining some logic?