Create a diagram that can change the X-axis label

It is really hard to answer your question as you have not shown
the incoming data, how the data is display at current time, how you wish the data to be displayed and how your flow is configured.
All this should be in a form that is copyable and well formed.

How to import/export a flow

There’s a great page in the docs (Working with messages : Node-RED) that will explain how to use the debug panel to find the right path/value for any data item.

Pay particular attention to the part about the buttons that appear under your mouse pointer when you over hover a debug message property in the sidebar.

BX00Cy7yHi

In order to make code readable and usable it is necessary to surround your code with three backticks (also known as a left quote or backquote ```)

``` 
   code goes here 
```

You can edit and correct your post by clicking the pencil :pencil2: icon.

See this post for more details - How to share code or flow json