The idea of names having power is ancient and mythic and practically universal across cultures. A magical name that describes the essence of a thing and gives the Namer control over it is a classic, and of course it seems like hubris when the Namee is more powerful than the Namer. I love it and thought I'd play around with some twists on the old mainstay:
0) If you know something's True Name you don't gain power over it. It gains awareness of you and starts taking an interest.
Whatever primal force you're trying to contact goes "Hey, who are you and how do you know my name?" Like if a frog suddenly called you by name you would probably pay attention and engage with it at least a little, even if you could just walk away.
1) A True Name is accumulated, not a single thing.
You're not born with a True Name and not everybody has one. You end up with one as you gain nicknames, epithets, aliases, and titles throughout your life. Once you hit a threshold of Names the collection of all of them becomes your True Name. Reciting all of someone's Names in sequence is what has power, and it does require all of the Names, including private pet names and what their parents called them when they were little.
2) True Names change frequently depending on where someone is and what they're doing at the moment.
Only one Name out of an entity's collection is the True Name, but which one it is changes with the aspect of their persona they're expressing. If you want to get the attention of The Charnel-Daubed Lady of War when she's at home with her family, you need to summon "Mom."
3) There's only one True Name out of an entity's collection of Names, and it's the one they like best and think describes them the most accurately.
Their True Name will change over time. To summon them you need to know them well enough to correctly choose the current True Name from their entire collection of Names.
* Giving people and entities new Names can alter them, but also protect them by increasing the size of their collection of names. While they don't have any power to control, Names definitely have the ability to influence their bearers.