Technology Trees (and Graphs/Maps generally)

I’m doing a bit of hobby coding for a game and I really need a technology tree for my game. I went looking for some online and found some stuff, none of it exactly what I’d like or aimed at what I’m trying to do. I’ve managed to code a hodge-podge of stuff that will just about do me for what I’m trying to write, but I’m learning that writing a generic system to display a graph/map-type structure is actually quite hard. Not reinventing the wheel would be appreciated, so I was wondering if there’s anything out there that people recommend?

more on the “behind the scenes” side of things rather than user interface; perhaps looking into the nodal editor windows would be helpful

That… is super helpful, thank you.

You’re right that it’s not directly helping me, but having a system where a tree could be sketched out or designed in the editor for prototyping before rendering it would be super useful.

(Plus, I hadn’t considered the usefulness of using Bezier curves for linking nodes together naturally. All the examples I want to emulate have sharp corners.)