Not to potions and bosses, and the Wither causing you decay status could bring you down quickly if you're not prepared and don't use potions of regen.
and it's still possible to die from falling on full health
using scaffolding helps prevent this when you're doing a tall building
but it is still dangerous in the Nether.
Slow and steady across the netherack ceiling is advised to avoid falling to your death
And in End it's even worse, if you die in the Void in there, your netherite armor is gone.
Just because you have the top tier armour in the game doesn't mean you're in God mode,
I meant invincible to strays, minus the slowness effect.