Alter url structure

Hi,
I need to change some url’s in sitemap due to url structure logic which is different from the sitemap logic generator.
I need to make some changes like instead of using taxonomy location name : https://<my domain>/lawyers/miami, FL , I need to change by code to :https://<my domain>/lawyers/florida/miami.

I installed the plugin and found that the right place to change and make url string manipulations is in render function in sitemap-core.php file.
I wrote some code that manipulate url string and it worked great.

After that I had to restore site from backup dated before plugin installation.
After installed again plugin and put again my custom code, it doesn’t work anymore.
Note: I’ve used Yoast SEO sitemap feature until plugin installation.

Why it doesn’t work anymore?