>When I am tired from work, I spend more time on phone after. And less time doing other more engaging activities. When I had easy workday, I am more likely to do something else.

I have a similar experience but I don't think this disagrees with the parent. My mental exhaustion makes me seek out low-friction "junk food" behaviors. But much like drinking after work because you had a long day, the phone exhausts you in another way. The cure and disease are one in the same here.