You should be able to use templates in the resource field, for resources where the URL changes for example according to time of day, etc.
My own use-case is that I’m trying to fetch my commute time from citymapper’s, at next-coming 9am.
I’ve tried to do this with the command line sensor and curl, but there seems to be a bug, where it doesn’t accept the ampersand in the URL.
As I understand it, the consensus is that you should make a custom component, if the endpoint you’re trying to use needs this level of complexity. ¯_(ツ)_/¯