I have read this part about Warlocks
You can transform one magic weapon into your pact weapon by performing a special ritual while you hold the weapon. You perform the ritual over the course of I hour, which can be done during a short rest. You can then dismiss the weapon, shunting it into an extradimensional space, and it appears whenever you create your pact weapon thereafter. You can't affect an artifact or a sentient weapon in this way. The weapon ceases being your pact weapon if you die. if you perform the 1-hour ritual on a different weapon, or if you use a 1-hour ritual to break your bond to it. The weapon appears at your feet if it is in the extradimensional space when the bond breaks.
Does the restriction only apply to the extradimensional space feature? or does it mean you just can't fully make a sentient or artifact as your pact weapon?