I am trying to read the graphics pipeline in OpenGL and learn few things but I am struggling to find a good starting point in the engine. The only thing I can see is the big picture but that is very shallow for how much I want to learn.

Any advice on that will help.
Thanks

OpenGL is not a maintained renderer path at this time, we focused on Vulkan instead.
This would mean that to learn the pipeline will be harder as you cannot follow the pipeline to delivery.

What if I start reading DX11 implementation. I just want to learn how the renderer works. I tried reading few books but most of them are old compared to CE 5.4

DirectX11 is a viable path you can follow from start to finish.
There will also be many tutorials and guides on the internet available to General DirectX11 implementations that will help also.

Is there any good starting point in CE where i can start reading and debugging the DX11 rendering path ?

You might want to start with basic examples online of general usage and setup of the DirectX11 API like setting up your swap buffer and vertex buffer and implementing a basic shader. Then you will have a much easier time digesting the specific ways CRYENGINE designed its rendering pipeline as you will know the general flow of using the API and what to look for.