To clarify she is making niku jaga basicly a meat stew. She put salt in instead of sugar. Depending on the family there is anywhere between a cup to two cups of sugar for a batch that large. So yeah it would be disgustingly salty. Soup base is usually mirin sake shoyu sugar broth usually dashi but beef pork or chicken base works. It is one of those every family does their own style sort of thing.
Joke is it really isnt a quick fix, even 40min is pushing it. More like 2 to3 hours or longer. Just like western stew, longer it sits the better.
Also Japanese sugar is a off white so mixing them up is more of a trope than anything real. Also who has a bin for salt that huge!
Sugar is used a lot in Japanese cooking all yaki has it, sukiyaki is loaded with it. And if there is no sugar mirin is likely present or honey. Youtube "cooking with dog" and you will see how often it is used. (It is in english)
Sugar is used in a lot of cooking you just probably do not realise it.