0.5-1 year always the best.tyres are not food,u dont have to go for the latest.for example in 2018.buying 2017/2018 tyre is good.not much issue.the molecules of the rubber are more stable.

You'd used the  correct technical term here, cure.
In layman term, it is called 'hardened' or 'hardening' .
Personally, I would be too happy to be offered 3 year olds  against 3-12 month old , with  or without discounts.

Not for me, despite the fact that my XM2 was in use for  5.5 - 6 years over 110 - 120K km usage , considering tyre  manufacturers allow usage up to 10 years post production date .
I know journalists would be screaming scared .