For now, we have 2 strong contenders.
Our cooldowns synergize very well with Resonating Arrow. And apart from having great synergy with Resonating Arrow, Kyrian’s best soulbind is Pelagos which has Combat Meditation and Let Go of the Past. Combat Meditation gives you 350 Mastery for 10 seconds and Let Go of the Past gives you 1% reduced damage taken for 6 seconds every time you use an ability or spell that is different from the one you used before (this stacks up to 3%).
Night Fae’s soulbinds are really good for different reasons.
Night Fae’s ability Wild Spirits has very strong damage output as while the ability is active, every damaging ability we do will strike up to 5 targets for 35% nature damage. Wild Spirits on its own does about 25% more damage than Kyrian.
Dreamweaver which basically gives us a Cheat Death.
Hunt-Captain Korayn which amplifies your damage done to targets that have 75%+ health.
Soulbinds and Conduits
Finesse: Cheetah’s Vigor
Endurance: Markman's Advantage
Finesse: Cheetah’s Vigor
Eagletalon's True Focus - Trueshot also reduces the Focus cost of all of your abilities by 50%.
Surging Shots - Rapid Fire deals 25% additional damage, and Aimed Shot has a 15% chance to reset the cooldown of Rapid Fire.
Serpentstalker's Trickery - Aimed Shot also fires a Serpent Sting at the primary target.
Secrets of the Unblinking Vigil - When you gain the Trick Shots effect. you have a 50% chance to refund a charge of Aimed Shot, and cause your next Aimed Shot to not consume any focus.
Serpentstalker's Trickery or Surging Shots - You want to go for Serpentstalker's Trickery if the fight has 2 or less targets as you can maintain full uptime of Serpent Sting on both targets. Any more than that and Surging Shots gradually becomes better as well.
This is between Serpentstalker's Trickery and Surging Shots. Surging Shots is really good for scenarios that have 4+ mobs. But Serpentstalker's Trickery really wins in scenarios that have 1-2 mobs because you can maintain the dot with full uptime.
The percentage in single-target damage between Serpentstalker's Trickery and Surging Shots is high.
The trinkets from dungeons are not very good in Shadowlands. Inscrutable Quantum Device sims very highly, but as it is RNG based I would avoid using it. One other decent trinket from dungeons is Overcharged Anima Battery.
Apart from these, no other trinket is actually that good from dungeons. So what I advise is to farm honor and buy Sinful Aspirant's Badge of Ferocity and Sinful Aspirant's Insignia of Alacrity. From the raid Stone Legion Heraldry is good.
This is based on sims, so you should always sim your character.