Having been a devoted guardian of cats for most of my 6½ decades, I've always found that there is a very useful thing you can learn to do, if you haven't tried it already. Purse your dampened lips very tightly, allowing a very small quantity of air to remain in your mouth. Flatten your tongue vertically so that it forms the back of a triangle with your upper and lower sets of front teeth, and pull the air back, allowing a forced intake of air though your tight lips, making a sound like air escaping from the restricted neck of a balloon (sounds more complicated than it really is, but it's flippin' hard to describe!) If you can't master that sound, I suppose you could try abusing some balloons - that's a sentence I never thought I'd write!
Many people either don't know how to do this, or are too embarrassed to be heard doing it - but the noise you make is an absolutely guaranteed rallying call to all cats.
My mother used to do this all the time, and our dear cat Dinky would always come running from wherever he happened to be lurking in seconds, and all the cats I've ever had have always responded likewise. Once you've got them to associate that high-pitched 'squeakle' with you, you'll never lose them, as long as they're within range - and the range can be very extensive.
Regular practice will gradually improve your technique, and as you learn how to crank up the volume, you'll be surprised to see not only your cat, but others in the neighbourhood suddenly appearing from gardens well away up the street! (But a word of caution: try to ensure that the street has no traffic flow when you make the call, or cats may just come bolting out of gardens on the other side of the road, so fascinated by the sound that they run into the path of a moving car).
Good luck with finding your cat - I'm sure he'll turn up before too long.