on a related note - is there something like gltf but for 2d vector animation?

Weirdly, just a couple of hours ago I was trying to find this as an alternative "recommendation" for a buddy whom is digging around in this space. Couldnt remember the name of it, except that I had used it a while back for some simple lottie related work (and a couple of other simple tasks)... After trying various iterations of search terms that included the word "lottie" (and spending much longer searching than what I expected to) I eventually clicked through some link and landed on the Synfig site. And now, coincidently, this post shows up :)

Nonetheless... I have no idea of how this really compares to other tools, but when I have had a need, Synfig was a breeze to use for what I needed it for. Importantly, it was quick to get started with, and without needing to spend hours in tutorials trying to figure out how to do things. So happy user and all that :)

I've used this in the past and worked like a charm: https://opentoonz.github.io/e/

I've dabbled in animation in the past and this has some pretty powerful features. I'll be saving this for a rainy day. Looks great.