My first guess is that manufacturers of cheap chinese stuff don't bother with spice models.
Yeah I kind of figured that out. That's why I'm looking for something that might be compatible and have a model.
A second guess is that simulation would not be very useful. Parasitic properties due to PCB layout and of the used passives probably have an important influence on the end result.
That's clear, I understand the limitations. Main idea is not to simulate it down to fine details to see how a real PCB would behave, but rather to avoid setting the "exclude from simulation" flag on a bunch of components and adding makeshift substitutes like the voltage source spice primitives instead, which won't even be sufficient in case when I to use e.g. a variable output feedback divider.
I usually try to create a single nice schematic that works as such, works for simulation, and works for PCB design. Often it is quite feasible (for example, with MC34063A, if we speak about switching converters).