Your design and what you write looks like you are trying to avoid having GND pour under your tracks when it is absolutely opposite. Each current (supply or signal) flows in closed circuit. For most currents at PCB the back to source way is through GND pour. The smaller the area surrounded by a circuit the better - any current changes in circuit generates smaller magnetic field changes and as small as possible of any external magnetic field is flowing through your circuit generating unneeded fluctuations in it.
If each track has continuous GND pour under it then the area of circuit is the smallest (not 0 as PCB thickness is not 0).
Nowadays when we live in lots of strong magnetic fields everywhere (cell phones) this is more important than 40 years ago. The ways of designing PCBs that were good those times are no longer good.
I don’t design audio circuits so can’t say anything ‘for sure’ but you certainly should not avoid going with track over GND zone on the other PCB side.
Here is an example of my 2 layer (digital) PCB:
The idea behind it was to have continuous GND behind each track.