I dont know exactly what the issue is but when there are a lot of entities, moving parts (like redstone, or crops that grow), or detailed blocks (like signs, armour stands, paintings, chests) all cause low frame rates on playstation. Changing the graphics does not work at all. There are delays doing some things like not registering when mining a block or not registering the hunger bar when eating. There are also delays when hitting mobs or shoving them to move them, sometimes delays opening inventory, villager trade menu, game menu and basically anything that requires an interface, and doing these things when interacting with interfaces causes frame rate drops. Frame rate drops are intensified when playing splitscreen doing all these things, and the game should have a stable frame rate despite all these things. And the more people that are added into the game (Whether it is local or multiplayer) all these things are intensified. I can't remember all the issues that happen but these are some common ones, and since I'm on playstation 4 slim, I regurarly face low frame rates that are definitely not 60 fps playing on splitscreen. Playing single player is ok but delays are an overall problem like mentioned before not just on playstation 4 but I think on all platforms. Since I can't remember all the issues, all I can say is that the game just needs more stability in terms of frame rate on playstation and delays. When these issues are fixed, then the game would be much more smoother.