By endgame content I mean Crucible and Shattered Realms.
Resistance reduction (rr) is one of the most important things in this game. Widow is a must because it has stackable rr (-35%). Revenant has flat rr (25reduced). The former you take wherever you can. The latter doesn’t stack so one source is enough. Since you have none on your gear, Revenant is currently the best source. Another one is Manticore.
If you like Doombolt, ofc, knock yourself out. It’s about fun after all. But there’s way more dmg in supporting AAR wherever you can. Devastation is way more powerful than Doombolt but it needs much cdr and Aeon to reset its cooldown.
Evidence: [1.1.2.4] AARMAGEDDON: Spellbinder (Crucible 5:43)