Here's a video on SDF models in blender but: 1. the plugin doesn't seem to be released yet 2. it seems to be more for models than live rendering. EDIT: There is a plugin for Godot, haven't tried and 4.0 capability is a maybe, also comes with a few caveats

Personally even NURBS* (for 3D) and true vector (for 2D) live-rendered inside a game engine would be nice, though I even like untextured polygons (2D and 3D) for their fidelity. Here's an animated eye I made using a new Godot 4 feature (I mostly lurk because I'm not really a developer and not interested in using the popular languages). (more basic meme image thing made with Godot 3) (also of course Godot has SDFGI for 3D, plus SDF fonts)

There's also the lack of vector painting (auto-smoothed brushstrokes to create blobby vector shapes) after they killed Flash. Wick Editor is one option for that, though (probably a good option for animation, but code seems to be limited to JS).

*= though even having some basic shapes (sphere, cylinder, cone, etc) that allow some adjustment and are fully smooth without being highly tessellated would go a long way. I can't say quite the same with 2D as making a leaf using 2 verts would be something I'd do.