Link to external url data - dynamic date for stock data price monitoring

I’m using Calc to monitor stock positions.

Inserting an external link to this stock price url works fine:{insert_here}&startDate=2021-3-1&columns=open,high,low,close,volume,divCash,splitFactor,adjClose&format=csv

I get a nice input into my sheet:

What I’d really like to do is have the “startDate=2021-3-1” portion update automatically to the current month.

I’ve tried using “&{cell_ref}&” to replace the date, but to no avail.

I have had a look at the answer on How to use WEBSERVICE and FILTERXML calc functions?, but don’t see how this will help me. I have also searched around elsewhere.

Does anyone have a work around?