It's possibile to synchronyze two distant clock?

There's no sense to "the time dilation is symmetrical". The time dilation is relative. If the clocks agree at the meeting point that's the best you can do. Whether they agree when they are apart is motion dependent and since all motion is relative there is no fact-of-the-matter about the synchrony of distant clocks, even if they are not moving relative to one another. If they are not moving relative to one another, then they can be synchronized by assuming the light signal velocity is the same in both directions. But that synchrony only applies at rest their frame. And there is no direct measurement that can show the speed of light is the same in both direction, as explained in https://en.wikipedia.org/wiki/One-way_speed_of_light

But it is also shown that no experiment will contradict an assumption that the speed of light is isotropic. The Michelson-Morely experiment already shows that the two-way speed of light is isotropic. The abberation of starlight shows that the one way speed doesn't vary with the speed of the source or the speed of the Earth thru the aether. So the only other reasonable theory is that the emitted, outbound speed is different from the returning speed. But that would be contradicted by the use of radar repeaters. So while it is possible in any particular of measurement of light speed that the one-way speeds are different; there isn't any coherent theory of what this difference would be, nor any reason to assume it's not zero.