Drawcall Optimization for Canvas UI Using Sprite Atlas

Hi I have so many Sprites used on Canvas UI in my project. I am using Sprite Atlas to bring them into single draw call . But Sprite Atlas is not rendering them in minimum draw calls . I used Frame debugger where I found TextmeshProUGUI present on screen is breaking them into different draw calls . How to solve this thing and optimise my draw call count .
Unity version 2017.3.1

Thanks in advance for suggestions