> But referring to all these "4D dynamical worlds" sounds overhyped / scammy - everyone else calls 3D space simulated through time a 3D world.
In the research community, "4D" is a commonly used term to differentiate from work on static 3D objects and environments, especially in recent years since the advent of NeRF.
The term "dynamic" has long been used similarly, but sometimes connotes a narrower scope. For example, reconstruction of cloth dynamics from an RGBD sensor, human body motion from a multi-view camera rig, or a scene from video, but assuming that the scene can be decomposed into rigid objects with their individual dynamics and an otherwise static environment. An even narrower related term in this space would be "articulated", such as reconstruction of humans, animals, or objects with moving parts. However, the representations used in prior works typically did not generalize outside their target domains.
So, "4D" has become more common recently to reflect the development of more general representations that can be used to model dynamic objects and environments.
If you'd like to find related work, I'd recommend searching in conjunction with a conference name to start, e.g. "4D CVPR" or "4D NeurIPS", and then digging into webpages of specific researchers or lab groups. Here are a couple interesting related works I found:
https://shape-of-motion.github.io/
https://generative-dynamics.github.io/
https://stereo4d.github.io/
https://make-a-video3d.github.io/
All that considered, "4D dynamical worlds" does feel like buzzword salad, even if the intended audience is the research community, for two main reasons. First, it's as if some authors with a background in physics simulation wanted to reference "dynamical systems", but none of the prior work in 4D reconstruction/generation uses "dynamical", they use "dynamic". Second, as described above, the whole point of "4D" is that it's more general than "dynamic", using both is redundant. So, "4D worlds" would be more appropriate IMO.