I am nearly finished with the game and there were a lot of things that affected the experience and gameplay for me.
I have played FF7 Remake and liked the way they did that, it was very unique and I think it was the overall better game. But for FF7 Rebirth and their whole new open-world system, it ruined that experience.
1. If you have played Horizon Forbidden West, they have practically followed the same map/open-world gameplay as theirs, which I am not a big fan of.
2. There is this one AI robot that ruins the gameplay experience, once you explore through the game...you'll see why. There are several regions that you'll have to go through as well which he will guide you through.
3. The game goes through several sudden chapter changes compared to FF7 Remake, which will throw you off a bit and maybe the entire story. Again, you'll see once you play through it.
Other than that, they kept everything the way it was. The combat system, the story, the characters, and added a lot more new things to the game. I would strongly recommend playing FF7 Remake first before going into this, it'll just make everything more confusing if you don't.