I die constantly even in normal mode since I reached Act 3. Even with going full in on tadpole powers. I had to save scum the fight with Orin until Hold Monster finally landed and abuse the Ghoul summon to even stand a chance. She otherwise downed me in two or three rounds. The Tribunal of Bhaal fight was impossible on the first attempt. I had to first kill the guards outside as a separate encounter to be able to survive. The last battle in Shar's cloister would have been a wipe too, if not for the ghouls. And now Cazador just wiped my party. The only reason I can even win fights isn't because of my character build; it's simply from the OP powers the game gives you. I cannot play the game anymore, I have to game the game now. It sucks. Act 1 and especially 2 were way, way easier.
What build/party comp do you normally use? And what level are you?
I usually go with Swords Bard (1 level of Cleric for RP and, conveniently, Bless), usually with Laezel (EK with GWM), Karlach (Berserker 5, Thief 3, rest Monk, Tavern Brawler) and Gale (Divination Wizard), it's been pretty easy on Normal in Act 3.
I will say, if I had had something like all Rogue Astarion and Trickery Cleric Shadowheart in the party instead of Laezel and Karlach, it'd be significantly harder - everyone except me has high mobility, and everyone except Gale has very high HP (thank you 23 CON amulet) and pretty high AC. Having a Bard means I can be more aggressive with Short Rests, too, because you get 3. Divination Wizard means you have some control over whether certain vital rolls work without having to save-reload. Gale hands out Haste, usually to Laezel, and my Bard/Cleric hands out Bless to everyone (cast with a second-level slot), which means Laezel has 6 attacks per round and good luck to enemies trying to live through that (I use items like the Underdog gloves to try and ensure she has Advantage to negate the GWM penalties). Gale has tons of +1 save DC items so nobody can save against him and my Bard has 22 CHA and I think one of those items so it's very hard to save against her.
Karlach I might respec now they fixed the +3 returning trident in the patch just now, maybe lose the Monk levels.
One spell I've found particularly nice is Confusion - because if you can get it to land on the majority of the enemies (and it usually does) - their ability to coordinate and perform well is basically completely destroyed - even if they attack, it tends to be a random target, rather than the smart target. I think whatever table Larian is using it's slightly less bad that the PHB one (which only gives a 20% chance of not doing something worthless and a 50% chance of doing nothing at all), and it only lasts 3 rounds rather than up to 10, but the default radius seems to be larger and to grow more when upcast.
I don't have any powers, never eaten a tadpole.