Take out 2 siphon soul, 2 stone hill defenders, and 1 twisting nether
Then put in 2 mountain giants 1 more faceless 1 spell breaker and 1 tar Creeper (I have prince taldaram instead of tar Creeper but tar Creeper is a decent budget option instead of prince) but this is deck is really hard to play so keep that in mind
take out siphon soul, really? i feel like that has helped me a lot when opponents bring out some super powerful cards. could you explain a little for me?
At some point you are going to have to look at all the advice people have given you and really think to yourself about a couple things
What kind of deck do you want? Do you want it to have all the removal? Should it stall as long as possible? Should it have a lot of greed with cards like Nzoth and Rin? Should it have more early game? Do I need doomsayers to stall? Do I need mountain giants to beat other slow decks?
Cubelock is a deck that doesn't have a perfect list, because the meta is not one dimensional. At the top end you have to deal with extreme greed of other warlock decks, jade druid and raza priest, and hyper aggressive fast decks as well as midrange decks with huge value and tempo.
Think about what you want, and what you feel like you're lacking. Only you can get comfortable with your own deck and only you can see what you're struggling with in your individual matches. Don't go on a crafting frenzy, just try to balance the deck the way it fits for you. Especially because cubelock is a skill intensive deck to master and constantly changing your list won't always fix things. Adapt your list as you get more experienced and see where the holes are. Don't judge anything after a few games, play a long stretch and see what you can do better, in both gameplay and deckbuilding.