What is Braum's most reliable build when he mainly has to break the enemy's first offensive read?

Braum's most reliable build is the one that lets him protect his carry from the first enemy engage without losing all of his presence right after. If your item order helps him do neither, it is missing his real job.

When should you truly adapt Braum's build instead of simply pushing the standard tank support route?

You should adapt as soon as the enemy draft stops you from playing the kind of fight Braum wants to defend. If you need to absorb more poke, reach the fight faster, or answer a specific damage profile, the purchase order has to move early.

Which enchant should Braum choose when the real issue is mainly holding and then replaying a second denial?

Locket often remains the most reliable choice when Braum mainly needs to absorb the enemy's first response with his team. If this enchant makes the first defensive sequence easier to play, it gives a lot of value.

Braum Wild Rift Best Build Guide (Patch 7.2a)

Braum’s value comes from absorbing initial damage and slowing fight tempo. The build focuses on damage mitigation, defensive auras and extended survivability.