If you’re looking for Cory Doctorow to support Apple in any way …well, don’t hold your breath.
I don’t use GPG/PGP but it looks like there is at least one current, mature product: https://gpgtools.org/
Also, if you want to try to reduce the risk of email snooping, why not consider a move to MyKolab.com - a service that I use and happen to like because they are seriously, seriously committed to protecting their clients’ privacy by 1) being located in Switzerland, a place with excellent privacy protections and a culture of maintaining rather than reducing those protections 2) running a paid-for service so there’s no need to sell your information to the highest bidder 3) using their own hardware, located in Switzerland, to support the service rather than farming it out to someone/somewhere else.
