OMG I LOVED Flatland! There is also Sphereland, but especially considering when it was written, Flatland was by far more innovative and creative. Sphereland was an homage btw, not written by the same author, and instead much later, slightly updating things to include Einsteinian physics.

Okay in that case, you might be interested to know: C.S. Lews - the author of Chronicles of Narnia, and well-known apologist for both christianity and atheism (hehe, he switched, then switched again:-P he left his childhood religion behind, became atheist, then became a different type of Christian) -has this trilogy starting with "Out of the Silent Planet". I highly recommend it for anyone who wants "imaginative scifi", in the spirt of Flatland. It is less known than his fantasy works, I suspect b/c the details did not hold up well in historical hindsight, e.g. all of those creatures on Mars and Venus that we never did end up finding... but it was nevertheless quite bold in its risk-taking in that regard, having been written prior to that - even though he knew reality was not going to end up anything like that, yet he made this fantasy work anyway:-D. Also I love the neat way he has of making you be skeptical enough to question EVERYTHING that you believe:-).

In that series he puts forth basically exactly what you are describing. These are beings within our universe, but are entities of energy whose only way to interact with our world is... well, imagine how you would interact with a bacterium: you'd have to make a puppet and say "this is me", but lol it really isn't. And yet, from a certain POV, it kinda is? Like the best way to talk to "you" is to walk over to the puppet and engage with it, which your set-up would likely be predicated upon, as in even if their entire universe is observable under a microscope slide, still that is where your camera is pointed and zoomed at.

I also thought it was neat how planets are these dirty little mud-balls, in the eyes of those who literally fly through space - to us they are our entire worlds, but to them they are navigation hazards!!:-P We are the bugs that splatter on their windshields? Or perhaps the mud-balls are dangerous even, like reefs to a boat. Another interesting point was that space is not as "dark" as those pictures from the moon would suggest, b/c of the light streaming outwards from the sun (this one I can never do justice to the explanation, and anyway it may have been just more fantastical world-building material). The first and second are wonderful depictions of what it might be like to travel to Mars and Venus, while the third is more abstract, being on Earth but they do wake up King Arthur, in order to fight against aliens acting as demonic spirts that possess the spirit of a beheaded psychic kept alive with like lasers or something, so... there is that:-).

So many scifi series - like Star Trek - do such a wonderful job of showing us these imaginative concepts. But still there is something to reading them rather in books (or listening via audiobooks I guess), and since these were never made into movies, that is pretty much the only way to experience them. Enjoy!:-)