Since I don't know how difficult getting the Floor 100 Nyzul Uncharted Region gear (the Thaumas set) might be for you, I'll exclude that from my recommendations for now.
TP setup adjustments
The new Aluh Jambiya makes for an arguably better offhand dagger than the Str path Thokcha, thus making it a better dagger to offhand than your Str Kila.
Swap out the Agasaya's for a Rancor Collar (with capped Tonberry hate). Even though the +10% damage taken sounds like a lot, on most mobs as far as regular melee attacks, it's only going to add maybe 10-20 damage to you at the most. Likewise, you should have an evasion or a -DT setup for situations where you might take a lot of damage, and have something else thrown in like a Torero Torque or Twilight Torque.
While Ocelot's are okay, I'd recommend changing to Brego due to the better stats for the sake of melee that you'd be getting from them (more accuracy, Str, etc).
Don't use Hecatomb Hat for Sneak Attack. Since Sneak Attack is a normal melee attack round, +Slow gear factors into your attack delay, thus resulting in it taking longer for your next melee round to go off. If you have the funds, an Ocelomeh Headpiece +1 is your current best bet as far as a Sneak Attack headpiece, and will also be the best for Rudra's Storm as well. If you can't afford that, the NQ is a fine substitute.
While Agasaya's is ok for now, try for a neck piece with a good amount of Dex, like Moepapa Medal or Love Torque for SA. Using the Gorget is fine for Rudra's. For Evisceration, use an appropriate elemental Gorget and a Rancorous Mantle (gain the boost to fTP from the gorget and +5% crit hit rate at the loss of 5 attack and 2% DA)
Pixie Earring is fine for Sneak Attack, but if you can get one or already have one, the Attack +4, TP Bonus +25 augment combo from the Moonshade Earring from finishing Wings of the Goddess is the best earring alongside Brutal Earring to WS in for Rudra's and Evisceration (Rudra's because the +25 TP goes towards damage, and Evisceration because it goes towards +Crit Rate)
Though it's not much of an upgrade, Athos's Tabard over Loki's Kaftan if you can obtain one. Same amount of +crit hit damage, but slightly higher levels of Dex. Also has the +acc on it as well.
If you're active in doing Voidwatch (especially Provenance), aim for the Wanion Belt, as that will be your best piece for Sneak Attack and Dex based weaponskills (Rudra's, etc). If you aren't, I recommend using a Cuchulain's Belt over Chiner's. One less Dex, but given Thief's relatively low base attack, the +10 Attack is a significant boost to damage.
Try to work on getting Athos's Tights for SA and Rudra's/Evisceration. Though you're losing 6 Dex, you're gaining +4% crit hit damage, which pushes Athos's ahead slightly. Furthermore, if you have Athos's Tights and Tabard, you gain an additional +2% crit hit rate from the set bonus, which works well for unstacked Evisceration.
Same as what was said about the Ocelomeh Headpiece +1 for Sneak Attack. NQ is a good substitute if you can't afford the HQ.
Swap out one of the Drone Earrings for Brutal for Exenterator
Ocelot's is okay for now, but try to get Athos's Gloves for Trick Attack/Exenterator. One less Agility, but +7 Strength as well as a +fTP bonus if you WS on the proper day (the wording on the hands are inaccurate, as it doesn't affect just elemental weaponskills, but affects all weaponskills with skillchain properties matching the day i.e. weaponskills with Detonation properties will receive a +fTP bonus when those hands are used on Windsday)
Stick to Atheling for your back piece. While the AGI on Blithe is nice, since Thief is a relatively low base attack job, +20 Attack will do more for Exenterator as well as Trick Attack.
Don't use Sveltesse. For the same reasons as using Atheling over Blithe for the back, that's a lot of attack to give up for the Agility you'd gain. Use a waist piece such as Crudelis (3 less Agi than Sveltesse, but +5 Str and no -attack) or Anguinus Belt (+15 Accuracy, +15 Attack, Double Attack +1%) over Sveltesse.
Keep Epona's on for Exenterator (unless you stack it with Assassin's Charge). The overall damage boost from a possible Double or Triple Attack going off would push Epona's ahead of a +Agi ring in the long run.
Closing suggestions/Thaumas set
Thaumas head for Exenterator, Trick Attack, and potentially Evisceration
Thaumas body for TP purposes
Thaumas hands for Utsu casts
Thaumas legs for Exenterator, Trick Attack
Thaumas feet for Evisceration, Rudra's Storm, Sneak Attack, Trick Attack, Exenterator, etc.
If a few pieces are paired together for certain situations, they'd prove to be better than they are as stand-alone pieces due to the set bonus.
Tessera Saio from Provenance Watcher for Exenterator at the very least, though could pull ahead for Rudra's, Evisceration, Sneak and Trick Attacks due to the +Str and +Att at the loss of a little Dex, Agi, and crit damage.
This was just sort of a general idea of things you can work towards. Hope it helps.
My thoughts and reviews
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