Actually no -- things like FaceTime are more like 90 ms, while other common products like Zoom and Meet are around 150-200. These are minimums with somebody in your own city. This is actually from my own testing in the past, where FaceTime was the clear winner, since Apple cares a lot about latency and is custom written for its own hardware.

But networks absolutely can add major latency, have you never had a slow Zoom call? It's because of congestion building up and radio interference. That's what leads to things like 1,000 ms latency, which makes back and forth conversation very difficult. Perceptible latency issues are always because of the network.

And yes products do time stretching but that's also what people often call glitches because it's very weird.