The beast Syldra has been slayed. After some rejigging of team to survive opening turns, first real attempt mastered in 27.91:
Team
Aerith (LM1+LM2): R3 Dispel, R4 VAligarmanda, Ace Striker (USB2)
Squall (LM1+LM2): R5 Life Siphon, R2 SSS, GAthering Storm (BSSb2/AOSB), double ice boost
Elarra (LM1+LM2): R2 Hastega, R4 Curada, MM (USB1)
Sora (LM1+En-Ice LM2): R4 SSS, R3 Shellga, Scholar's Boon (USb/AOSB), double ice boost
LAguna (LM1+LM2): R3 Icy Offering, R3 Freezing Snipe, Battleforged (CSB/USB1), double ice boost
RW: Guardian
MAgicite: Manticore (L15 Enpower Ice x2), Mateus (L8 Spell Ward/L10 Dampen Wind), Phoenix (L8 Blade Ward/L8 Spell Ward), Siren, Evrae (L8 HP Boon)
Squall had 10/30 HP and 20/30 ATK/DEF/RES waters, Sora had 30/30 ATK, Laguna had 10/30 HP/ATK, and Aerith/Elarra had 30/30 HP/DEF/RES/MND.
Sora was rocking that fire/ice/lighting+ keyblade we just got, BTW.
Very rough turn order:
Aerith: Dispel, Valix2, USB2, Valix2, USB2, Vali
Squall: RW, Life Siphon x3, BSSB2, CMD1x2, CMD2 spam, AOSB when near 40% mark, CMD2 spam
Elarra: Hastega, USB1 after Thundaja, Curada, Magicite, USB1, Curada spam, USB1
Sora: Shellga, SSS spam, USB, SSS spam, AOSB near 40% mark, SSS spam
Laguna: Icy Offering x 3, CSB, USB, ICe Offering/Snipe spam depending on number of IMperils, USB
These turns are very rough because I literally just ran this, LOL. I'll update this with corrected turn order if I run the fight again soon.
So. This was my first time fighting Syldra. I had a different arrangement of the team and Squall and Aerith had swapped RMs, and I couldn't get past the Phase 1 Turn 5 Thundaja. Needed Wall, Shellga and Hastega up ASAP, needed to Dispel by 3.74 and have Elarra ready to heal by 5.50. Rearranged my team to the above, mastered and sub-30'd first try.
I was a bit worried it wasn't going to work, since 15 seconds in and I hadn't even gotten out of Phase 1. Chain didn't drop until around 13 seconds in, BTW. But thanks to some imperils stacked and near permanent HQC from the healers, Sora/Squall/Laguna started pounding away and took down her HP astonishingly fast. The AOSBs didn't even hit close to max damage, probably because Savage mode was up - Squall got 55000x3+80000 while High Stakes was up, Sora got 80,000, which I'm hoping weren't all critical cause that would suck for next time. I'll definitely have to wait for Manticore to break Savage first before I fire the AOSBs off.
Regardless, Squall BSSB CMD2 still did 9999x7 even with High Stakes up. Syldra still had about 200,000 HP left after both AOSBs, but Squall/Sora/Laguna still chewed through it. But holy shit at that Phase 3 damage! YIkes! Definitely need Last Stand there!
I don't know how sustainable this is since I had a couple dualcasts from Squall for 9999x14, not to mention it probably relies on a lot of early imperil procs from Laguna, but I'm confident it can improve (and not get worse). I just hope it's not too RNG-based.
In the end, Sora USB+AOSB, despite being a year old, still puts in work in a team. And it seems I didn't need Squall USB4 (or Sora AASB, for the matter, though I still wish I had it!) after all. Still, this win couldn't have been done (or at least not done as easily) before today, when I snagged Squall's AOSB in the second free 40 pull.
11/11 5* magicites attempted sub-30'd now. Just Adamantoise left (haven't fought it as yet). Need to build up Syldra and do some more deck building first. But I'll leave that for now. I just wanted to see if I could beat Syldra right now. Now that I have, it's back to crystal farming.
OH! Last thing: I honed my second copy of SSS, which I only got recently, to R2 but ended up never actually using it. Squall was all Life Siphon and burst commands. I'll still keep it as a just in case, but I find it hilarious that I've still yet to deploy 2 xSSS in any serious fight.