I'm just here to point out that your question is nonsensical. You're asking for propagation delay of the wires vs switching time of the gates, but you don't wan

I'm just here to point out that your question is nonsensical. You're asking for propagation delay of the wires vs switching time of the gates, but you don't want the propagation delay to be measured by the time it takes for a signal to be propagated or the switching time of the not gate, so you are instead asking the total propagation delay to be normalized by the switching time of a not gate and somehow calculate that back into a wire length equivalent normalized by the longest dimension of a not gate. None of these things make much sense. Also as an approximate answer to your question: The simplest circuit without a flip flop aka an oscillator can easily reach hundreds of GHz using silicon germanium based semiconductor manufacturing