Let me know if I’m hinting too much, but I thought I’d drop a clue or two in spoilers to move you toward new challenges.
A small point of clarification regarding text that you’ve encountered: You found Nomai text referring to the south pole of the Quantum Moon. The text stated that you always land on the south pole. This text refers to an observation; it does not refer to instructions. The angle or location at which you approach the Quantum Moon will not affect where you land there.
Some thoughts about Brittle Hollow, specifically the Black Hole forge district: while it is entirely possible to turn your ship upside-down to land up there, it’s extremely fiddly because that’s not the intended method of reaching this area. Even if you get up there, though, the forge won’t be accessible unless you’ve done something elsewhere in the city first. First hint: it’s not the school district. Second hint: it’s not the Eye Shrine district, either.
If you want to make progress on Dark Bramble, I’d encourage you to find Esker’s signalscope log which is located on the Attlerock. If you’ve done that, and you don’t see why it’s relevant: the notes draw a connection between Dark Bramble and something happening on Timber Hearth. You need to find the connection. If it’s still not clear how to proceed, expand the additional spoiler below:
A critical technique for navigating Dark Bramble
There are two techniques, actually, but I’m only going to explain the first one, for now:
There’s only one source of harmonica music, but it’s coming from two locations. If you follow it to Timber Hearth, you get to a Dark Bramble seed that you cannot fit through. What happens if you follow the second source of harmonica music into Dark Bramble, though…?
Regarding the room full of spiky plants on the Ash Twin: like most challenges in Outer Wilds, it’s not about agility, it’s about timing. If that doesn’t give it away—wouldn’t it be easier to navigate if you had a surface you could stand on that was above all the cacti on the floor?
If you haven’t been inside the High Energy Lab yet, you definitely need to revisit the lowest level of the Sunless City. Again, I recommend you take the hole in the rocks next to the gravity cannon to get there, but it’s possible to arrive with enough time even if you take the long way from the escape pod.
Not sure whether you have the DLC, but that’s what the deep-space satellite signals are for. While it’s relevant to the overall story, it’s a completely separate bag of hammers; I wouldn’t pursue it while you’re in the middle of figuring out the main game.