I think it's hilarious that we get kinda ticked off if the Universe doesn't fit our eqations. The sheer scale they are describing makes my head swim but I also realize that no one really "knows" what anything is.
They say the galaxies move but not one of them have moved enough to even register since humans have been watching them. According to the math, they SHOULD move and they are assumed to be moving incredibly slowly. Not saying the galaxies are not moving, just that what they are seeing are readings on their equipment and they are theorizing about what the readings mean. In many cases they are spot on, but science still contains some dogmatic ideas that are an article of faith like any religious dogma.
I don't think we were seeing a photo of it. I think they use alot of artists' renditions of these types of astronomical features. The video didn't work for me so iono.
Basically, the Universe is stranger than we could ever imagine. Our "fantasy" stories are just mash ups of stuff we've actually seen: like Pegasus, horse with bird wings. Dude with one eye instead of two, or even three eyes. Snake hair, bull head, three headed lizards, man turns to wolf. Etc. No one really creates anything new and if you could it would prolly not be as interesting as all the real shyt. So yeah, the Universe's ability to strike awe far outpaces our ability to expect it. We'll never know the limits.
Even so, they could somehow be wrong about the size and nature of this cluster. There's no way to actually measure how far away it is or the size, they just have to judge by the brighness of standard candles and shyt like that. Dope stuff, may or may not be exactly what they think it is