Here's how I do it, I'm not sure if it is the most efficient method, but it works in at least Table Charts.
I create a column that contains the text I want to show and another that contains the URL i want the text to link to. You can see that in
https://docs.google.com/spreadsheets/d/1kjOTQMAlWc-j6G_XfFUJIzAxuvmyxygQh0q1Dpn4oRU/ where the Name column is the text I want to add the URL to.
Once I've got the datatable, I get the number of rows in it, then step through each row, combining the Name and URL to make the link
var totalRows = crewDataTable.getNumberOfRows();
for (i = 0; i < totalRows; i++) {
// Create the link in the name column (index 0)
var txt = crewDataTable.getValue(i, 4);
if (txt !=null) {
name = crewDataTable.getValue(i, 0);
newURL = '<a href="'+txt+'">'+name+'</a>';
crewDataTable.setCell(i, 0, undefined, newURL);
}
You can see the finished table at
http://hmsgambia.org/crewlist.htm I used the same technique on
http://hmsgambia.org/crewbios.htm but that only collects data where the URL column is not empty (null). There's nothing much else on those pages so looking at the source should show you the code fairly easily.
There's another technique you can use and that's adding the URL to the tooltips for most charts. You can add almost any HTML to the tooltips and the documentation for doing that is at
https://developers.google.com/chart/interactive/docs/customizing_tooltip_content I used the documentation to add images to the tootips to a Timeline chart, but there's no reason you cannot add links. A working example of that is at
https://indstate.edu/business/history/faculty (that's a fairly long page so just use Ctrl + End to get to the bottom of it). The sheet for that is at
https://docs.google.com/spreadsheets/d/1MFDuFhqJGkEBSgbZd5t4KBcz06LPrRVVRykIom2LZzs/ - it looks a bit odd because the top timeline on that page is drawn using Timeline JS and that expects the data to be in a certain order and I use a single sheet to produce both timelines.