in terms of vanilla balance and non-pitch black runs, cove is the second easiest region in the entire game, barring crit horseshittery, the trick to fishmen formations is to simply disintegrate the first two slots as fast as reasonably possible, since unlike many other frontliners, they're consistent in just slicing your first two ranks, if it's hybrid formations get someone that can pull the fish in ranks 3/4 into the first two (occultist/shieldbreaker are the safest ones, bounty is a meme), and for a region that you should never really set foot in, is the weald since it has no rewards, the hardest hitters in the game are there, which includes the strongest champion special (the virago)
also for mods it has always been a coombrained siesta, and you mostly can thank weebs and chinks for it, which reminds me to ask, isn't black reliquary very coomer-ish in its artstyle?
The mods I'm using includes:
Shared: Home for Lost Monsters, Koala's Creature Collection, Here Be Monsters
Warrens: Bristle and Bone, DD2 Enemies, Swine Scavenger
Cove: Hunters of the Deep, Abyssal Horror (only at Champion levels)
No lewd mods, only misery (loves company) and death. Lots of it.
EDIT: Actually fuck it, time to unleash the Niggermania enemies collection:
General (adds enemies to all dungeons): Cho's Boss Reworks (except Croc), Home for Lost Monsters, Koala's Creature Collection, Here Be Monsters, Mimic Miniboss, Coven, Brigand Deserter, King Baldwin, Pelagic Hybrid, Maledictor, Darkest Soul enemies, Talon Brigands (from Falconer mod)
Roaming Minibosses: Crystalline Harbinger, Doomsday, Roaming Beast, Death
Warrens: Bristle and Bone, DD2 Enemies, Swine Scavenger
Cove: Hunters of the Deep, Abyssal Horror (only at Champion levels), Orcadian
Ruins: The Manor, Mendicant Friar (after Incandescent Whisperer quest), Marcus Brothers (only at Champion levels), Rotting King, Ectomorphs (from Beyond Mortality), Bonebranch Smackdown 2
Weald: Smoker, Lumberjack (only at Champion levels), Hallowed Harvester, Shrouded Chief, Vegetation Takeover, Banshee
Courtyard: Courtyard+, Kraken
Farmstead: Farmstead+, White Vvulf
Hamlet: Dimensional Havoc, Carnifex, Ringmaster, Incandescent Whisperer, Musician (only at Champion levels)
Sunward: Raiju, Festival of Light and Death, Night Parade
Other: Vermintide