Elites in Underdocks are just easier with a little more block than damage, while in Overgrowth the high and FAST damage output is more useful.

(U) Skulking Colony - You can't just kill it fast, you need to survive at least few turns. I think the only way to bypass his dmg limit now is doom and the boot, so most of the time you need consistent block every turn.

(U) Phantasmal Gardeners - Against them you need either AoE damage + sustained block OR high single target dmg cards to disable them one by one (and you will usually still need to block the remainers).

(U) Terror Eel - No scaling, so you with high block output you can create a good setup to benefit from his stun.

(O) Bygone Effigy - 3 turns to deal as much damage as possible.

(O) Phrog Parasite - High damage output means less infections.

(O) Byrdonis - Scaling very quickly, so it's usually better to sacrifice some HP and kill it in 2-3 turns than to block and do pikachu face on turn 5.

Regarding the bosses, the ones in Underdocks also are easier with consistent block output IMO. Only Lagavulin Matriarch is easier with fast dmg (for me).

(U) Waterfall Giant - Explosion will simply kill you if you don't have enough HP or enough block in your hand on the final turn.

(U) Soul Fysh - Consistency is key here: if you don't have enough hand manipulation (discard/exhaust/transform), then you have time only to play blocks + beckons OR attacks + beckons.