WW3 might be warned, discussed, threatened or anticipated by profiteers, but I doubt if it will be allowed to start unless by stealth or by accident. First and Second Tier countries who own such weapons know there is too much for all sides to lose, and any “victory” will be a rueful one of unending expense.
It’s going to take more than one little ol year to deflate the Monarchy.
The majority of Brit voters are still tightly bound to their traditions, far more intensely than most Americans are bound to their own. A true doing away with The Crown would take a slow gradual dissipation of loyalty and love for all things British.
On the other hand, Revelation says there will be blood !up to the horses bridles...