My recollection is that the briefing map shows the equatorial trench (let's call that running west-east although it's arbitrary I agree) and the trench they go down being perpendicular to that. check out https://youtu.be/TOgtj00Rp8s?si=2E5SieRc8-XMzUU5&t=20
(you may have to scrub back and forward a bit to convince yourself either way). The sphere rotates and you see the big equatorial trench and highlights a smaller trench perpendicular to that that doesn't extend the whole way around. The briefing zooms in to show more detail. That's the one they are going to go down.
It’s always depicted as traveling with the equator “level” relative to the camera’s arbitrary axis. The hyperdrive and sublights must enforce that. We actually never see any kind of exhaust like a star destroyer, no clue how it ominously hovers around. That adds to the menace.
At Yavin 4, it approaches gun-first since it is calibrating to fire. But the equator is still level with the center of the planet it’s orbiting, or perhaps the moons orbit plane.
Does it matter when approaching from space?
They could just as well meant an equatorial run as far as a spaceship pilot is concerned.
Would the Death Star even keep a consistent orientation while travelling in space?