Sorry to hear, I can understand this causes a lot of stress on your part.
1) It is highly unlikely they cancel your contract - They can continue to defer OR they may give you the opportunity to work in another office, but I doubt that they would cancel it
2) Non of us here can declare what "Pandemic over" means to KSA - read through their announcements, declarations etc. to get a better understanding of this.
3) I think you should ask HR if starting in another (any) office is an option
Overall, I think you should prepare to be delayed a year in Saudi Arabia (i.e., a likely worst-case scenario...though it could be longer or shorter). I think you should raise your concerns with HR and ask them what can/should be done.