If you want security it's out there but it ain't cheap. Most trailer locks can be breached with a trip to Harbor Freight Tools for a crowbar and a bolt cutter. These methods are cheap and one doesn't need much IQ to pull it off.
I just purchased an enclosed utility trailer to serve as a garage for my camper at my home resort. It will be stored at that location in the covered camper storage with my Jayco but we're really out in the boonies. Utility trailers are favorite game for thieves, as Alabama will not title them and stolen trailers can be sold at will. I purchased a Fort Knox coupler lock from
https://ftknoxlocks.com/. The cost for mine was $208 but it is a welded 3/16" steel plate clam shell with a serious pick resistant solid steel puck lock.
Pretty much oxy acetylene cutting torch required to get it off.