[mothered]

There’s an app called curve which gives you a virtual card. The way it works is it combines all your accounts into an app and if one card gets declined it will automatically switch to the other.

I know of Curve, but haven't looked Into It.

Now the curve card has its own card number and cvv. If I use that at checkout, will it count as a different payment method?

It will count as a payment method that's not associated to your previous/current accounts.

since the billing address I would be the same as my main card - ones I’ve used to se amazon before, will i be detected?

Yes, the address will be detected.