This may not be what you’re looking for, but I also often copy-paste from Excel into the body of a tiddler a lot. I just wrote a simple procedure to parse the paste values - in Windows it separates lines by newline and columns by tab. I save this off as a global procedure and then use like the below.
\procedure data(text)
<!-- This is so you can copy/paste in a range from Excel and make an HTML table-->
<table>
<$let newline={{{ [charcode[10]] }}} tab={{{ [charcode[9]] }}}>
<$list filter="[<text>split<newline>!match[]first[]]" variable="row" counter="rownum">
<$list filter="[<row>split<tab>]" variable="col" counter="colnum">
<th>
<<col>>
</th>
</$list>
</$list>
<$list filter="[<text>split<newline>!match[]butfirst[]]" variable="row">
<tr>
<$list filter="[<row>split<tab>]" variable="col">
<td><<col>></td>
</$list>
</tr>
</$list>
</$let>
</table>
\end
<<data "
Name Age
Adam 33
Bob 22
Charlie 44
">>