Extracting data from LO chart when its data unavailable

I want to extract data from charts without its data available (the chart was from a writer file).
I found one answer here.
Strangely, when I did that, there was a question:
“This chart currently contains an internal data table. Do you want to proceed, deleting the internal data table and set a new data range?”
When I choose yes, then the data range is gone (i couldn’t choose the tab Data Range).

I can see the data by Double click on the chart (or right click–>edit), then right click → Data Table... (or ViewData Table...).
Here I can see the data (including their error bar), but I couldn’t copy all the data at once (i can copy one entry at a time, which is painful).

Is there any other way to do it?
Many thanks!

Version: / LibreOffice Community
Build ID: 30(Build:2)
CPU threads: 12; OS: Linux 5.4; UI render: default; VCL: gtk3
Locale: en-US (en_US.UTF-8); UI: en-US
Ubuntu package version: 1:7.3.5~rc2-0ubuntu0.18.04.1~lo1
Calc: threaded

See the answer to a similar question: Chart not updating. Data table automatically created stopping Data Range automatic update - #11 by Villeroy

One more: How to export chart data table from impress - #3 by Lupp

Another workaround:
Paste the chart in an empty text document, save it as .fodt and open it with a text editor. Search for <table:table-cell office:value-type="string">. With some find and replace you can recover your data.