I never really had any "This is so bullshit" moments when I played through the game on PoTD, let alone on Tripple crown or my solo runs.
Its a matter of knowledge, you aren't supposed to play through the game on PotD when you first play the game, I played through the game my first time on hard just like any veteran would, it was hard at first when I didnt know anything, but I took a few steps back and did some trial and error until something worked.
Here are some basic steps to take, I've played this game now for maybe over 500 hours, so bear with me if that number isnt high enough, I've played solo on games like baldur's gate 1/2 and Icewind dale 1/2 for over 5000 hours combined, so take it as you will.
Fan of flames work if you have a decent mage, Scroll of fan of flames works wonders.
Use stuns/charms/paralyze/blinds: Pretty self explanatory, Ciphers can just make the shades/phantoms nie useless and basicly make them fight eachother and duke it out if they have to, They arent immune to charm/stun/paralyze/blind so there you go.
Have a Pale elf tank.
Git gud.
I've played this game over and over and over again using a vast number of different builds and tactics and I've never had any issues with these monsters, they are perfectly balanced and you just need some extra knowledge and/or patience with this.
Perhaps you lack patience. (Which is very apparent at this point.)
Dont bash the game for your lack on knowledge of skill at playing PoTD difficulty, its supposed to be a decent challenge, not a walk in the park. (I dont consider ghosts of any shape or form challenging, try troll druids with insect spam or the battery sirens/dragons instead)
This post is filled with arrogance and ignorance.
I will tell you again for good measure.
Git Gud.