Exploring Womp was informative. I won't revisit it soon though. The free version is very laggy, because of the constantly streaming nature of the online tool.
Also, the more interesting features, such as textures, are paid-only. The free features are very basic.
#MagicaCSG is the go-to tool if you'd like to enter the world of SDF modeling.
Saw it yesterday on the spur of the moment for the first time, without knowing anything about the story or the length of the film (a very important detail!)