Hi, we have updated from Kentico 12. It was no problem until Kentico 13 to have individual URLs structure.
Our agency have now created a "custom page URL" option. If "custom page URL" is specified, then the custom page URL is used for menu, sitemap and other. URL based on the content tree is redirected to the "custom page URL" with code 301 permanent redirect.
I hope it will not slow down our website.