Have not read all of this so apologies in advance if not relevant. I have also not watched the opening video.
45 pF/ft seems about right for an XLR cable especially if star-quad topology.
There are gobs of threads here and elsewhere discussing the impact cable LCR has upon the signal. Phase shift is coupled with the LCR parameters, you can't really separate them. The issue comes down to how much is in the audio band and how much is acceptable. For interconnects, bandwidths for typical consumer and pro audio gear studio interconnects is in the MHz range, so phase shift in the audio band is insignificant. Especially when laid on top of the immense amount of phase shift introduced by microphones, various mixer/preamplifier/processing/filter stages, amplifiers, and monitors (speakers).
Phase shift alone is not a problem; any time you have a cable length longer than zero (0) and non-superconducting you add some phase shift to the signal. How the phase slope (group delay) changes over frequency is more important. Non-linear phase shift leads to non-constant group delay, meaning not all frequencies are delayed the same, and then you get smearing in the time domain. This is a real problem in my day jon dealing with GHz signals; not so much in audio, or rather it is a problem mainly with analog signal processing (filters and such) and not with the cables themselves.
A system with 100-ohm preamp output impedance driving 100' of cable with say 45 pF/ft and 40 m-Ohm/ft (e.g. Mogami W2893) driving a 20 k-Ohm load (next stage in the chain) will have about 300 kHz bandwidth and about 3.4 degrees of phase shift at 20 kHz (solid magnitude, dashed phase).
View attachment 118741
If instead this is a speaker cable, the output and load impedances are much lower. If we use 100 m-Ohm amplifier output (pretty high these days, a damping factor of about 80) and a 10-ohm speaker (higher speaker impedance = more shift) with 16-gauge cable (~4 m-Ohm/ft so about 0.4 ohms for 100') and sticking with 45 pF/ft then the bandwidth is well over 10 MHz and phase shift at 20 kHz is essentially 0 across the 100-foot cable:
View attachment 118742
Interaction with the speaker's impedance will affect this result since the speaker is not a purely resistive load, nor is the amplifier's output impedance, but in practice the amplifier's output impedance and speaker's impedance is more important than phase shift in the wire.
At least IME/IMO - Don