The advantage of the Dauntless school is its low reliance on equipment affixes, allowing it to perform well even in the early season with limited progression. A basic lineup built with Rare/Epic heroes can still achieve impressive damage. Here is a brief guide to the lineup strategy for your reference.Summary: This lineup relies on Altair's battle skill as its main source of damage. When he casts his battle skill, every basic attack from an ally will trigger additional coordinated damage from Altair. It is recommended to equip him with the Manticore Statue Artifact to boost his battle skill damage, while activating the Relentless Charge talent to maximize his damage output.
For secondary damage dealers, it is recommended to use Dauntless heroes with high attack frequency, such as Shagrol, Vani, Nimbus, or Yagnatz. Choose one of them (excluding Vani) to equip with the Crown of the Unclean/Witch's Remains and stack certain Accuracy to inflict Defense Penalty on the boss.
For support, it is recommended to choose two from Garius, Catherine, Nathaniel, or Ihuicatl to ensure the team's survival. Equip them with the Brotherhood Spirit set and alternate their ultimate skills to maintain the 3-piece set's damage bonus throughout the battle.
In the early game, when your Elemental Affinity level is low, you can also equip your damage dealers with the Ancestral Guidance Mythic item, or replace one with Iola, who can inflict Attack Penalty on the boss, to ensure Altair's survival.
 Summary: The advanced lineup uses only one support hero to pursue higher damage output. It is recommended to equip all damage dealers with Ancestral Guidance to enhance their survivability.
In the Temporal Vortex, it is recommended to activate the Relentless Charge talent for Nastjenka to enhance her long-term combat capabilities. After activating the 5-hero Elemental Affinity, if you feel less survival pressure, you can consider replacing Ancestral Guidance with Imposing Presence to further increase damage output.
It is recommended to equip Sutha with the Puppeteer Revelation set to speed up the team's recharge. With sufficient Crit Rate, stack as much HP as possible on Sutha to make him the hero with the highest HP on your team, so he can tank the boss's Call of Lightning.
Ivellios has a high damage share in this lineup, but since his damage is primarily Enlightenment-based and his basic attack frequency is relatively low, he may not survive until the end of battle even with Ancestral Guidance. At a low Inspiration level, you can consider replacing him with the Epic-quality Nimbus or Shagrol to further increase the trigger frequency of Nastjenka's additional attacks.
Tharivol not only has an extremely high basic attack frequency, but his special basic attack after casting his ultimate skill also triggers Witch's Remains to inflict Defense Penalty on the boss. Therefore, it is recommended to stack certain Accuracy on him to ensure a successful infliction.
Besides Acilia, you can also consider the Epic support hero Ihuicatl. When well developed, she can also sustain the entire team on her own.
 It is recommended to set the Puppeteer Revelation wearer's ultimate skill to be cast after the damage dealers, to reduce the damage dealers' ultimate skill recharge time to under 18 seconds. Taking the advanced lineup as an example, here is a reference for skill timing preset: