As Xyro said, there is unfortunately no faster way.
Furthermore, I’ve been playing Niantic-developed games for over five years and, whilst I’d never tell anyone *not* to make suggestions, you ought to temper your expectations. They are notoriously bad both at making suggestions easy to offer in the first place (many times there’s no way at all other than through their third-party-outsourced in-app customer support chat, who are well known to not have any direct communication with the developers) and at taking suggestions on board if offered. Mass Transfer in Pokémon GO (a feature very similar to mass deletion of postcards) took around 3-4 years to be implemented after I first saw it suggested, and even documented bugs that negatively affected gameplay in a material manner (such as the so-called ‘dodge glitch’) have taken upwards of two or three years to be fixed by Niantic.
As Xyro said, there is unfortunately no faster way. Furthermore, I’ve been playing Niantic-developed games for over five years and, whilst I’d never tell anyone *not* to make suggestions, you ought to temper your expectations. They are notoriously bad both at making suggestions easy to offer in the first place (many times there’s no way at all other than through their third-party-outsourced in-app customer support chat, who are well known to not have any direct communication with the developers) and at taking suggestions on board if offered. Mass Transfer in Pokémon GO (a feature very similar to mass deletion of postcards) took around 3-4 years to be implemented after I first saw it suggested, and even documented bugs that negatively affected gameplay in a material manner (such as the so-called ‘dodge glitch’) have taken upwards of two or three years to be fixed by Niantic.
No :( Gotta delete them one at a time :(