I haven’t watched the podcast being referred to, but I’ll give you my experience and 2cents on the topic:
Recovering from injury (broken left hip and then 6 months later right hip), the L/R balance was quite valuable measure of progress (in addition to monitoring how much power I could deliver to the pedals before soreness).
My range today is 51/49 to 49/51, but seldom wider. The last 4 hard rides were: 50.1/49.9, 49.3/50.7, 49.4/50.6, and 50.2/49.8 (data from Training Peaks).
However, it wasn’t always this way. Three years ago, variations as wide as 47/53 occurred and 48/52 was common (I am right side dominant. What changed was strength training (in addition to more structured training). I am particularly convinced that leg exercises including single leg weighted calf raises, weighted step ups, and weighted lunges have been extremely helpful to creating both stronger and equal strength balance in both legs. While it is hard to isolate any single aspect of training to results, at age 61 I have crushed every PR of every length beyond Pmax that I set over the prior 15 years.