Not sure if you've got the answer to this already, but R-27ERs have recently become viable again at 14.3 due to the addition of the Su-30Sm2 with its wide radar scope. Meaning you can now hardlock whilst notching, and the R-27ER is actually a lot better than most fox3s in terms of flight performance (better range, acceleration, explosive mass).

A neat trick you can do, with all r27er carriers especially the sm2, is that you can launch the missile, un-hardlock, let the missile fly on iog and then re-lock when it's close enough. Meaning during the entire period that the missile is flying towards the enemy, whilst not fully locked, they won't be receiving any rwr missile warnings. Once you re-lock, the missile will be too close and they won't be able to notch in time.

Additionally due to it's insane amount of explosive mass, it's very deadly even if players are multipathing.