A habit that I've taken up which makes me quite happy and I think solidly helps my focus is working offline.

Some days, I'll set a timer for two hours, and then just work offline for those two hours.

I have most of the documentation for tools I use available offline, I'm a bit math enjoyer so I have like 5GB of maths textbooks/papers to study, and programming offline, especially when you've got docs for everything you use, is not only still doable in the LLM age, but also quite enjoyable :)

Reading the article, basically all of the distractions the author mentions are internet-based (HN, LLMs), so perhaps adopting an offline work habit might help them too :)