I'm currently making a game based almost entirely on non-linear dialogue with no plugins or addons.
Using a pure text parser and a made up scripting language for that. I already had this game published twice using other frameworks (Corona SDK, Unity) and now remaking in C3 due to the fact that it is just faster and easier to develop; and WAY less error-prone due to how Construct does not allow for programming errors/typos to be made instead of hitting you with warnings after the fact.
So you should be fine.
If you want to use JSON or even an online database that's also well within Construct's capabilities.