Beating the first three brutal challenges in Final Fantasy VII Rebirth on your first playthrough can be challenging but is achievable with the right strategies and builds. Here’s a detailed overview to help you through the first three brutal challenges:

### Challenge 1: Setup and Initial Strategy

1. **Materia Setup**:
– **Yuffie**: Use Crescent sickle as her weapon. Equip her with SM R armor for good defense and a speed demon keychain to slightly replenish ATB when an action is taken.
– **Equipment**: Ensure Yuffie has Titan summoning material, HP up, speed up, Elemental link to fire, HB charge rate up for weapon skill opening ATB bonus, and other supportive materia.

2. **Initial Strategy**:
– **ATB Management**: Keep Yuffie’s ATB topped up by casting spells like Fate and Life Safer. Use Steel Skin on Yuffie to reduce damage taken.
– **Team Coordination**: Have Barret watch Yuffie’s Mana Wall and Haste. When these abilities are low, cast them again to keep them active.

### Challenge 2: Adjustments and Tactics

1. **Round 1**:
– Be mindful that the bird sometimes flies away, which can restart the challenge. If this happens, restart the challenge to avoid wasted time.
– Focus on dealing damage quickly. Use Guaga on all enemies to clear them out easily.

2. **Round 2**:
– Use the same trick as in Round 1. Guaga is effective against most enemies, making this round relatively easy.

3. **Round 3**:
– This round is more challenging. Watch out for the Yin and Yang enemy, which deals significant damage. Use Quake on Cloud to stagger the enemy and then finish them off with Quake again.

### Challenge 3: Final Preparation

1. **Materia Swap**:
– For the third challenge, you might need to adjust your materia setup slightly. Ensure you have enough resist materia to protect against elemental attacks.

2. **Combo Strategy**:
– Use a combo of spells like Arcane Ward and fire magic on Gilgamesh, who is weak to fire.
– Keep your ATB topped up and use Mana Wall and Haste to maintain a high damage output.

### General Tips

1. **ATB Management**: Keep your ATB boosted and topped up to ensure you can act quickly and maintain a high damage output.
2. **Elemental Weaknesses**: Use elemental weaknesses to your advantage. For example, Gilgamesh is weak to fire, so use fire magic effectively.
3. **Team Coordination**: Ensure your team members are using their abilities effectively. Barret should be casting Mana Wall and Haste to support Yuffie.

By following these strategies and adjusting your materia setup accordingly, you should be able to beat the first three brutal challenges in Final Fantasy VII Rebirth on your first playthrough. However, practice and patience are key, as these challenges can be quite demanding.