Loglines are hard for creators, because we are attached to our stories, and the aspects that make those stories interesting, tv guides are not. You may be having difficulty because you think you need to sell your story in the logline. That's really not what it's for. You sell your show with advertisements, trailers, banners, etc.
My current film is over 5 hours long now, and many things happen within, but the logline is just
"A cat is trapped in a surrealistic maze, and must find a way to escape."
In the film, the cat faces dangers, it solves a mystery or two, it travels across worlds, it makes friends, it descends into hell, it floats weightlessly through a space station. It's a horror movie, a sci fi movie, and I could go on to say a thousand other things about it, but as you can see, I didn't include any of that in the logline. It's just the essential core of the story, as minimal as I could make it.
Some people do make them much longer, but I think this comes from the aforementioned fallacy that people are buying or watching the film based on the logline. It's important that it's good, but unless you can display some wit within the logline, it should be pretty minimalistic. I have seen ,for example, a comedy movie that managed to fit a decent joke into the logline, thus demonstrating the film's humor, a selling point for that genre.
Here's a good resource,
Loglines are vital in the pitching and conception of an idea. We take a look at 105 famous logline examples from popular TV shows and movies.
industrialscripts.com