I know the feeling, Mantis.
Once when I was walking in the neighborhood at night, someone drove by and asked me if I saw a dog. He lost his dog and was looking for it all over the places at night.
The thing with cat is, sometimes they aren't intentionally trying to "run away" from your home. They could simply get lost on their way to explore the world. Although I do not believe it is common for cat not be able to find their way home. Sometimes they could be grabbed by other people. One time I had a unknown neighbor's cat walked right into my door as I just got home. I could have had the cat if I simply closed the door. I had to keep my door open and show the cat way out. It could be the case with yours.
A GPS tracker in the collar would definitely be the best way to track your cat.
