Three account perks

Melee Tempo
Halves standard melee attack delay against NPCs, rounded up with a 2-tick minimum. PvP and special attacks are excluded.

Berserker Focus
Increases melee damage dealt to NPCs by 5%.

Guardian Resolve
Reduces all damage received from NPCs by 5%.
Melee Tempo and Berserker Focus support melee damage. Guardian Resolve helps with NPC damage, but food, prayers and managing the boss and minions remain essential.
Equipment upgrades to consider
Obsidian Life Spark
A successful weapon hit has a 20% chance to restore 1 Hitpoint.
Obsidian Bulwark Thread
Each non-zero incoming hit has a 5% chance to deal 20% less damage.
Obsidian Aegis
Each non-zero NPC hit has a 1-in-12 chance to deal 25% less damage.
Bring normal boss-ready melee gear and supplies, and check God Wars access requirements in game. Put Life Spark on the weapon, Bulwark Thread on a head, body or legs item, and Aegis on a body or shield.
A useful swap
When survival is stable, replace Guardian Resolve with Boss Instinct. Bulwark Thread only has a 5% chance to reduce a hit by 20%; it is not a constant defensive bonus.

Before you spend
Check perk compatibility, compare permanent upgrades and review Forge materials. Socketed effects require worn matching gear; they cannot bypass the one-Tempo or one-Focus rules.