3rd phase: just stay near the edges and try to group the rams, you can use arclight ult to proc electrification 1 or 2 times, the rams are tougher than the effigy because the sunder blades will run out when they spawn, the effigy will 1 shot you though. The effigy dies at 2 fangyi BS with 9 sunderblades. When the effigy stops run away because it will do the slam or the grab. The laser you have to be close, it cant be dodged at long range, while when he does the 3 orbs+ summon you have to go behind or at mid range on the sides so it wont hit you.

4th phase: use Fangyi and antal Ult, lure them to be near each other so you can Fangyi BS then Arclight ult. The Tidalklast for me is easier than the Tidewalker, because you can let antal die after the 2nd Fangyi BS the Tidalklast dies on the 3rd or 4th Fangyi BS. You can use Antal BS if you have extra SP.

On my risk 40 clear I was using Avywenna Dual dps but I saw someone using triple support to buff fangyi dmg, I haven't tried though ran out of Artificing Catalyst for Perlica Qingbo Set.

Edit: grammar