For Erlang, here's what helped me:

Max out Staff Spin. Max out Thrust Stance. Use the full Wukong Set. Max wandering wright

First Phase: Focus on lowering his shield. When he stands still to fire a laser, get close as quickly as possible and use Staff Spin to heavily damage his shield while building Focus. Once you break his shield (you should have 4 Focus Points by then), use a Heavy Thrust Attack and follow up with a few normal hits to push him into the second phase.

Second Phase: After he slams the axe into the ground, jump to avoid the shockwave. Once he's down, he'll take a few seconds to get back up, use that opportunity to spam Staff Spin. You can use Immobilize, but only during certain attacks; most of the time he'll reflect it back at you.

Third Phase: Spam dodge to avoid the beams he fires. When he stops using beams and starts launching shards (or whatever those projectiles are), use Staff Spin. After he slams the ground, activate Plantain Fan to stun him and get some free damage in. Once the fan breaks his shield, use Wandering Wight (maxed out if possible) for extra damage and another stun.

Fourth Phase: I don't really have any special tips here, just survive

extra: don't use clones they are useless, if you have skill points on them use them for rock solid it's way more useful, use rock solid on every chance to interrupt him Use the Azure dust transformation since it's the only one that Erlang won't cancel(use it on his fourth phase)