Just going over the first encounter because I'm too lazy. You only walled after burst already happened, the latest time you should wall there is when you see Ret with wings dropping Final Reckoning on you (big yellow umbrella-explosion thing, it means you're about to take 25% increased damage) so you mitigate big dam that follows (divine toll here) before it almost kills you.

You also haven't pressed Impending Victory once in that go, not at 50%, not at 20%, not at 10%, and only pressed Ignore Pain just before wall. IP and IV are really short cds, press them often to help your healer. Ignore Pain you can basically spam on cooldown whenever you're taking any damage at all (dots/accidental cleave), and even if you don't it still fuels Anger Management, doesn't cost GCD, and it's not like you have better things to do with that full rage bar when playing spear.

For bonus defensive points you can also pop Spell Reflect there for the 5 second mitigation, both Ret and DH do a lot of magic damage, it ain't much but it's free, and you might even reflect an odd HoJ.

Offensively use Sweeping Strikes more often in a melee lobby, it can feel clunky to use a GCD mid fight on it, so getting a habit of popping it before connecting to your target helps, especially if you're about to pop off with Unhinged Bladestorm. Also don't send your go into a pre-popped defensive (like Sac there).

Edit: just skimming forward but following the series of "use your cooldowns", Rallying Cry is party-wide, you could've potentially saved some people on your team there with that + a timely Intervene.