Is this a style of chess?

Are there players who are a little weak at middlegame and openings so they just try to keep a positional/material balance and exchange as often as possible to create imbalances for the endgame and then dominaate the endgame. like thats their strategy. is that a good strategy at all to just be a chess endgame'ist?

Capablanca. But he was still really good at the other parts of the game.

I guess you could add Akiba Rubinsten and Ulf Andersson to that list.

I think you have to play to your strengths. Some people have a strong positional understanding and tend to to well in simplified positions. If you find these positions interesting, play them, if you find them boring, search for something more dynamic.

However, Ulf Andersson said in an interwiev some years ago that in order to compete in the absolute top (he was top ten ca 1980) today he needed to play more complex chess, and he couldn't do this. So if your goal is to be a top 10 player in ten years, don't play positional chess aiming for a small advantage in the endgame.