You might gain benefit from Ñāṇavīra Thera’s Notes on Dhamma; particularly the essays/chapters on Fundamental Structure, Anicca, and Atta. I could be very off base so I encourage you to read them for yourself - but here is my understanding.
Anicca is a perception of “the” (your) experience of phenomena, rather than of phenomena simpliciter. Truly seeing Anicca is itself supposed to induce dispassion towards determinate things. You will start to feel like you’ve had enough of the things you used to crave, that they’re just not worth it. Everyone knows in the external sense that things are impermanent and imperfect. The puthujjana’s thinking is that “well, they’re good enough for now, they’re worth craving”, and it’s even this more moderate belief that seeing Anicca is supposed to relieve you from.
So, to really observe Anicca, for example if a thought of lust arises, think about what you have to gain by the object of lust (not the object itself). No one would have sex if it wasn’t pleasurable, so analyze the pleasure. What comes before, and what comes after? Is the whole process in total a net benefit for you over the alternative? How much is the net benefit? On what other states, things, or actions does the very nature of sexual pleasure depend that might lower its value? Does any positive value gained persist? Precisely what is going on during the exact moment of gratification? Think about these things solely in terms of what’s going on in your experience.
Anyway, I say all of this just because your distinction of invariant reality vs impermanent instantiation seems to border on Platonism. The “invariant realities” you discuss are only invariant under one level of analysis. They themselves are impermanent instantiations of an even more fundamental invariance, and so on, which is why they are covered under the 3 perceptions as you said. All of these are fabrications. The structure is self similar across scale, and there’s no discoverable fundamental ground for any of it (and there doesn’t need to be for us to stop suffering).