I think it very much depends on the story. Crime and Punishment by Fyodor Dostoevsky, had a relatively short epilogue (if my memory serves me right), but it was crucial for the story.

I like a short epilogue as long as the book's central story has already wrapped up nicely. In that case it's a bonus that gives the curious reader a look at the future without bloating the plot structure of the main text.
I just finished Philip K. Dick's Flow My Tears, The Policeman Said which gives a quick summary of where the characters and institutions end up in a few years; it's important for reinforcing the book's social commentary while maintaining the power of the central story by keeping it streamlined.

When I finished the last chapter of crime and punishment I was moved to tears and thought I had just read a masterpiece. Then I read the epilogue and hated it so much it almost ruined the book for me lol. I understand it was important for giving Dostoyevsky’s “answer” to the nihilism presented throughout the book. But it was so heavy handed, completely lacking any subtlety whatsoever, completely lacking humour whatsoever, and completely different in tone than the entire rest of the book while lacking everything that made the book special. Also the last chapter ended everything so perfectly it really didn’t need anything added to it imo.

I cen see your point and maybe it's my worldview that resonates more with Dostoevsky's, but to me the epilogue was a very nice "send off" for Raskolnikov. But as I said, I can see why it's not for everyone.

Fair enough. I personally like stories ending on a more ambiguous note.

I think you're looking at epilogues the wrong way (if there is a "wrong" way). Epilogues aren't meant to be an ending; epilogues are what happens AFTER the ending. So if it feels like an abrupt ending, that's because it's not an ending. It's just a "Hey, this is what happened later, after the story was over."

Romance as a genre loves an epilogue. You are in for A LOT of them if you stay in this genre.