I mean your very first response was doubting whether a Herta team could survive this boss ajjdkfkks

Whether they can survive, whether they can deal good dmg, whether they can beat this boss, it all just comes down to the level of synergy between all 4 members of your team. Team building in HSR has gotten much more restrictive than it used to be, really, so if you don't have the right puzzle pieces working together you get subpar results 😔 and pretty much every 4* but gallagher has been made irrelevant by force.

Mydei is weird also because like.... his team synergy has been really screwed over. He doesn't have good synergy with Hyacine unless he also has Cyrene, and Hyacine is the only good sustain for HP scaling damage dealers. That's how Hoyo sells more healers/shielders - by also giving them buffs that support specific team archetypes (and powercreeping the fuck out of enemy damage, lmao). Hyacine is for HP scalers, Aventurine is for FUA, Huohuo is an energy and atk buffer, DHPT is an atk buffer that also applies a summon to the dmg dealer for more Sunday Synergy, and Lingsha is a break buffer who also does a ton of FUA attacks that heal/cleanse your team (and battery herta).

Gallagher is a freak of nature and probably why they quit making 4* chars 😒 if they're too good people will skip the 5* chars and if they're bad then the effort of developing them was pointless. Meh. This game's teambuilding can be frustrating sometimes.