UI Design - seveal screens sharing controls

Hi,

I'm building a trading App in Unity. It's not a game and it's mostly UI screens and menus.

In this app I have a menu and several screens where each represent a "Trading Game" of some type. The former programmers of this app made a god screen that has the UI elements for all the games and has conditioning inside to know when to hide/unhide elements , change colors etc. This thing got complicated fast and problem is I have to add more games. But I want to do it good this time.

For example I have Game A , Game B and Game C Where all of them shares a Graph Control and a Scrollview.

Possible solution.

1. Build prefab from scratch for each game with Instantiate it and keep it in memory.

2. Make exterior prefab with the Graph and Scrollview and add plugable prefabs to specialize the screens and/or change stuff on code.

I'm sure there are other better solution to this problem. I heard that linking prefabs is a better way of doing such stuff but I don't know how it will all play together in union. I also read a lot of ppl recommending saving UI layouts in external JSON/XML and I don't understand what's good in that.

I'm trying to imagine what would be the simplest way to add more games from UI perspective. What easy number of steps I would have to take. And I can't for some reason visualize it.

Any help would be greatly appreciated