Solve a problem with Selenium to "headlessly" sign on to Fidelity.com and download a .csv file

I'm developing software to create investment analysis for myself. It requires that I automate the process of signing on to Fidelity and downloading a .csv file containing my personal financial information, as well as another .csv that contains market information. I have used the Selenium IDE in Chrome to record the steps, and can successfully use it to download the required information. But I want to implement a "headless" solution that doesn't require me to initiate the action from the browser. The steps in the sign on and download process are saved in a .side file. The Chrome Selenium IDE extension uses that to perform the actions successfully. Selenium supports two ways to run headlessly. It generates code in a variety of languages that can be called, and it has an executable called selenium-side-runner that reads the .side file and executes the actions described in it. I used the export function to output the python code to do the download, but it fails, with the Fidelity site signaling an error. In addition I've used selenium-side-runner to run the .side file, and it fails also, in the same way. I'm hoping I can find someone with Selenium experience that can help me get the python version working, or worst case, selenium-side-runner which I could start from python. BTW I've received questions about using Katalon. Using Katalon studio, I wasn't able to successfully record the sign-on to Fidelity without the site throwing the same error as above.