How much timezone overlap can you really sustain?

Job posts say "4 hours overlap with US Eastern" as though it costs nothing. From Lagos that is a 2pm to 10pm day. Doable for a month. Harder for a year. The people I know who have lasted longest in US-hours roles did one of three things: negotiated the overlap down once they had proven themselves, moved to a team with an EU anchor instead, or worked async and defended it hard from day one. If you are working across a big time difference: what hours do you actually keep, and what did you have to negotiate to make it survivable?