Unable to edit chart data in Word

Hello,

I’m desperate to find the answer to my question in various forums, but to no avail...
The question might seem silly, and I’m sure the answer to my problem will be quite simple.

Here’s my problem. I just want to insert a bar chart into a document for work: a performance report of the services that my manager leads.

So I did the following:
- Insert a chart
- Bar chart
- I modified the data with the Excel table that opens automatically, everything modified fine.
I formatted my chart.
- I saved and closed my document

AND THIS IS THE PROBLEM: when I reopen my document, I can no longer modify the data, the entire 'data' tab in the 'chart design' section is grayed out.

The purpose of this document is to share it on our Outlook drive so that everyone can fill it out every month and, for example, update the '% of budget' section that I illustrated with a chart.

But even I, when I close and reopen my document, cannot modify the data of my chart.

I’ve tried different formats, but nothing works...

HELP!!!