Full house is not that hard. All you have to do is have your opponent resign before you lose any pieces.
What is the hardest achievement to get on Chess.com

Its Peaceful Victory.
You have to checkmate without anyone resigning, Running out of time, or stalemate.

Its Peaceful Victory.
You have to checkmate without anyone resigning, Running out of time, or stalemate.
I know its in a YouTube video, but it's fake

Puzzle addict just takes time. Even if you didn't pay for membership, it would just take just over 9 years.
And let's face it, if you've been playing every day for over 9 years, you probably got membership in there.

Puzzle addict, definitely. However, Castling Victory and Killer King are hard in the higher ratings, as opponents tend to resign. I got them when I was like 700 or something. Now at 1200, and I can't imagine anyone that would shuffle around on the back rank, trapped by a queen/rook while you ran your king there to discover checkmate. Also, in these ratings it's practically imperative to castle unless you have a very big opening advantage or something.
i got full house on one of my first days
its easy