Honestly? It didn't came across as "realistic". But as an over-the-top comically dark deconstruction of a Happy Ending, equally unrealistic as the perfect shining "lived happily ever after" would have been.
The same way I can't fathom the depiction of violence in DIS to be "realistc", when in reality it's just as comically over-the-top in the opposite direction - Quentin Tarantino-like blood splatters, but still no real portrayal of actual violence and the physical and emotional consequences it really would have had....
For Star Wars, I'd have much preferred a more sober, realistic scenario. With wins and losses. Not just extremes to one side of that.
Like having the New Alliance and Empire be in a cold war-like scenario. Have the Alliance be a successfull thing, but the Empire still stronger. Or having Han and Leia's child turn to the dark side, yes, but not their only child, and turn their marriage into a failure as well. It was just...too much. The old heroes should have had at least some successes - not even Obi-Wan and Yoda became THAT defeated and hopeless after "Revenge of the Sith".
Every character and goal was broken to the point that it stopped being tragic and became unintentionally funny again - like watching a cartoony train wreck. It didn't feel like a legitimate "story" that was told, but essentially a never ending sequence of "Hah, gotcha'"-moments the writers tried to create be upending all expectations - but the material became a pure parody of a story in the process. (Again: This wasn't "The Last Jedi"s fault - this was already unchangeable put in place in "Force Awakens". That movie just didn't care about those implications)
The "Classic Trilogy" heroes had over 30 years of personal success and prosperity; the end of that success and prosperity doesn't invalidate anything that they did prior to the tragedies and problems that befell them and the galaxy.