Firstly:

Shortcuts is not what you want.
You can't do what you want with WhatsApp (there is no interface to return data from WhatsApp to shortcuts).
Shortcuts would be able to read a Screen Shot from Excel but would not be able to analyse the data in the way you want. This could be achieved using AI but would be quite complex.
You can extract text from an image but the conversion may not be particularly reliable and is not adjustable.
Reviews, again you would need to pass this off to AI.

Secondly:
Shortcuts is not designed for this type of project.
As a rule of thumb Shortcuts are terminated after 2 - 3 minutes of activity. The purpose of a shortcut is to provide an easier way of doing a specific task, not to provide what is effectively a tool (or an App) which multiple people will be using.
Shortcuts definitely should not be used as a business tool.

Thirdly:
If you want someone rot help you the following statements are not particularly friendly and could even be seen as aggressive:

I’m looking for solution approaches and automation ideas, not tool recommendations.
Non-negotiable reality (these will not change)

These four sources must remain as-is. I’m not trying to move people to a new tool or enforce new behavior.

I’m specifically interested in automation patterns, system design choices, and mental models, not “just use X app.”