Hi JDK,
I am Sumit, an Independent Advisor and a 3 year Windows Insider MVP here to help.
You appear to be running the initial release of Windows 10, called 1507. WSL is supported in 1607 and higher. With 2004, you get WSL2.
Try updating to version 2004 using the Media Creation tool and if it fails let us know.
The fastest way to get the upgrade is through the Media creation tool or ISO file.
Please download Media Creation Tool from the link below and select Upgrade this PC at the first screen.
https://go.microsoft.com/fwlink/?LinkId=691209
All steps, including upgrading using ISO file and Media creation tool, are covered here:
https://www.yourwindowsguide.com/2020/05/featur...
Content on the above blog is written by a Microsoft MVP so it is safe.