No one is overreacting. Flipkart has cancelled hundred of iphone orders in its last year sale. Then it happened with 6700xt. Then many received different items in the next sale, plenty of posts on facebook regarding that.
This time thankfully everything went fine.
Also, it doesn't matter if the warranty is not available because of Flipkart or because of seller.
The point is, warranty is surely available, but from the import date only for any 2023 bought card unless the card is imported just 3-4 months back.
Zotac has confirmed it from their official mail and has clearly mentioned a buffer of 90 days otherwise no extended warranty will be given. Other brands do not have extended warranty so buyers are still in dark.
It is upto a buyer to decide according to the import date he gets if the card is worth the price or not.
You can choose open box delivery and reject the brick.