Hm… If the 30 minutes is onerous, rather than just disappointing, there’s a slightly different method you could try in the interim. This compresses on the remote Machine before attempting transfer:
https://community.fly.io/t/pg-dump-always-gets-interrupted-while-backing-up-postgres-db/23842/12
Moreover, since that download is a distinct step, it is natural to use SFTP or rsync, both of which are better at WAN connections than the Postgres protocol is. (Possibly, part of what is hurting performance suddenly is the sjc ↔ sea latency added into each operation.)
A different user had luck with just uploading the dump file to Tigris from within the remote Machine, 
…