Hello big fan of Fallout here, i just have one question i choosed hardcoe mode on and difficulty mode very hard but i get my ass kicked a lot so im thinking to changing just the difficulty mode to Normal instead of very hard but still keep the hardcoe on, so the question is will i lose the hardcoe achievement if i scale it down from very hard to normal ?

The hardcoe mode achievement should not care about difficulty. If it does, then it's a bug.

Are you sure about that? The only way to lose hardcoe achievement is to turn off hardcoe mode itself?

Within reasonable doubt. Anything's possible, but then again, the penguins could be a superintelligent society of aliens simply studying humanity if anything's possible.

hardcoe mode achievement is granted for completing the game in hardcoe mode without turning it off.

How can we know for sure? because i changed to normal and i feel i killed enemys much more easy

That's because you changed the Difficulty. hardcoe Mode has no effect on the damage you do.

That's irrelevant. hardcoe mode is not difficulty of killing enemies. It's just some survival sim elements.