You link ego depletion (willpower depletion and decision fatigue alternative terms) to working memory, based on neuroscientists refusal to reify the former. But you neglect that, neuroscientists would deny that working memory is "a thing."

The psychological findings are robust. That the first-proposed physiological explanation is dubious doesn't disqualify the phenomena.

The opponent process theory in mentioned in the wikipedia article is promising.

Who says willpower limitations are a function of limited capacity? This is something of an engineer's favored explanation. A better explanation is probably rooted in evolutionary psychology rather than inherent capacity limitations. We evolved with opponent processes governing control and gratification.

Attributing willpower depletion to "distraction" isn't an explanation. Distraction probably has causal relevance, but it isn't a magic wand to wave away psychological findings.

The OP is amateurish.