As Canadane said, make sure to pair Sheltron with another CD - while it's really strong, the others will cover the tank buster and any damage before it. This means learning when the tank buster is coming, so you can have the big CD up for the damage before the TB and Sheltron up when she starts swirling green stuff.

Just some extra advice:

- Planned Hallowed usage is really strong in this fight as it avoids the need for a tank swap (Rampart + Sheltron -> [swap] -> Rampart + Sentinel -> [swap] -> Hallowed -> Rampart + Sheltron, as an example). However, sometimes things don't go perfectly as planned, so what I personally recommend is if you've used Hallowed before the Hallowed buster, use Sheltron + Convo. If you've got a SCH or a Diurnal AST you can get a buffed shield from it, and it should be alright. Basically don't be afraid to pop Hallowed if it's necessary outside of a TB.

- DV is strong in this fight, especially in 2x WHM groups. If anyone has weakness or Vuln Up after the adds die, it's a good place to DV. On top of this there are parts where Sophia will spam her AOE in bursts, which is another good place for it. A more niche potential use is to prevent the knockback from the head on everyone, but this might require a bit of coordination (basically if the head knockback does 0 damage you don't get knocked back)

- Speaking of this - Tempered Will! And Cover! TW will prevent the knockback from the head, and anyone Cover'd by you will also not get knocked back. I'm 99% positive that TW also works on the tilt, but I've never actually done it so someone would have to let me know if I'm wrong there. If that is the case I imagine Cover would also work on that as well.

- Don't forget to use Awareness. Also I thiiiiink Sophia's auto attacks are physical (can't remember) so I guess try and pop Bulwark at some point. Clemency can have niche uses, just don't use it to heal yourself up as soon as the TB smacks you as you could rip hate back just from that (depends on the tank, obv).

e: Oh you're a tank. Well. WHATEVER THERE'S SOME ADVICE ANYWAY. :P