I am not going to get into the why you need a true mobile site in this post, but you can get some info about that HERE.
Here is the simplest way to get a great mobile site with your Divi WordPress Theme. This is pretty basic which is why we have a store with mobile layouts and why we build so many custom mobile sites for our clients. This post however will get your mind headed in the right direction.
Create a new Page and call it MOBILE
Under page attributes / template select blank page.
Now Publish your page.
STEP TWO (optional)
Go to Appearance / Menu and create a new Menu
Add any links or custom links you want added to this menu.
Call this menu Main Mobile and save that menu.
Go back to your new mobile page and start adding sections.
First section and row is full width menu.
Now add a Standard Section full width column with an image module. (Logo)
Now add a Standard Section full width column text module. (Tap to Call Button)
Now add a Standard Section full width column text module. (For Custom Buttons)
Now add a Standard Section full width column text module. (For Social Icons)
Now add a Standard Section full width column text module.(For Footer Area)
You can find the mobile redirect plugin we like and how to use it HERE..
If you want you can make other key page names just for mobile also. www.yourdomain.com/m-about, www.yourdomain.com/m-services, wwww.yourdomain.com/m-location ect.. ect… Then link to these pages via your dedicated mobile site.