Is an offensive or defensive build better on Sophia?

I don't use Sophia so I don't have first hand experience but from what I've seen most people run a defensive Raven tome build on her since she has great defenses but low speed. I imagine an offensive build would be really creative and need quite a bit of investment, though it would be really cool to see. Hope this helps! :)

There's this guy on my friend's list who runs a +10 +Atk -HP (though -spd would be better IMO) Raorowl++Res, Swap, Iceberg, Close Counter, Quick Riposte, Atk Smoke 3, Close Defense 3, and it's seriously beastly when I've used it in RD/GC. That's a 44/48 defenses against melee with 3 teammates next to her, without buffs or the smoke proc. A lot of fun to use, and really tanky.

I think defensive. Her attack is not that great, her speed is through the floor but her bulk is quite good on both sides. Here is mine, the only expensive thing was w.Tharja but gave both the weapon and CC and I don't like Armored units. You could use an Owltome as well, and I've seen some with TA and raventome being useful.

I don’t know why GP recommends an offensive set for her.
For builds, definitely defensive, with TA-Raven, or Radrowl/Candelabra+CC

I think this image should give you the answer you need. Literally don’t even try an offensive build for her; Lilina and Sanaki can pull it off better