Thanks for this question!
I'm certainly no expert on Country and the pitching/sync placement of it, but happy to offer some general advice. Likely Nashville is the place to be, and getting on board with a solid publisher with roots there (Secret Road for example), could be a good way to go.
I've never used Music Xray and they can be great for lower level acts, but remember you'll be in a giant pool of artists and getting through that can be very tough and often a very unpersonal experience. Companies like Sentric Music are a good option too. You can't pitch through ASCAP, they are just a publishing PRO, there to collect and distribute royalties.
Build relationships with publishers or other songwriters, practise your craft as much as possible. Finding a good publisher who can get behind you as a songwriter is always the best option!