This is a rough guide of how you should progress your atlas once you get to maps. You should do at least the 1st Hilda beast mission too to get the powerful boss node for the atlas ascendancy. Powerful bosses are how you get higher tiers, every powerful map boss will drop you a waystone that is a tier higher than your current one, it is impossible to not sustain if you aim your path through the boss maps.
Don't bother leveling any league mechanics at this point because they dont drop much at low map tiers anyways. Just focus on rushing the fortress. Once you kill the Arbiter of Divinity you should venture out further into the atlas going in ONE DIRECTION, DO NOT DO RANDOM MAPS. Just keep pathing until you find Matriarch and Patriarch halls to get boss fragments to fight the Arbiter of Divinity again, as every time you do this you'll get another ~40 atlas points.
Once you get past the 120 points on the tree below it is up to your preference what to take, dont overthink it too much since you'll get all the points eventually.
If your build sucks dont take any effectiveness of monsters nodes