URL is kind of a weird one. In Adobe Analytics, it's only available in Data Warehouse. Outside of that, it's not available. Because of this, almost every organization uses an eVar that's dedicated to page URL.
When I implement Analytics, I'll almost always use eVar1 as page URL. My typical implementation for it is to set eVar1 in the global variables section to:
%window.location.hostname%%window.location.pathname%
That removes duplicates to different protocols as well as query strings, resulting in a lot less cardinality for the variable. You could also use a second eVar that includes protocol and query strings if they're valuable in your organization.