Many feeds include links to so-called enclosures, like audio files for podcasts. While your mail is not processed by MUA, its new/ messages are still there, so you can run enclosure downloading process, that uses GNU Wget. Each enclosure’s filename is more or less filesystem-friendly with the current timestamp.
$ ./feeds-encs [...] monsterfeet.com_grue.rss/encs/20220218-152822-traffic.libsyn.com_monsterfeet_grue_018.mp3 www.astronews.ru_astronews.xml/encs/20220219-115710-www.astronews.ru_news_2022_20220216125238.jpg [...] $ file feeds/**/encs/*/ monsterfeet.com_grue.rss/encs/20220218-152822-traffic.libsyn.com_monsterfeet_grue_018.mp3: Audio file with ID3 version 2.2.0, contains:MPEG ADTS, layer III, v1, 96 kbps, 44.1 kHz, Monaural www.astronews.ru_astronews.xml/encs/20220219-115710-www.astronews.ru_news_2022_20220216125238.jpg: JPEG image data, JFIF standard 1.01, ...
feeds-encs does not parallelize jobs, because enclosure are
often heavy enough to satiate your Internet link. wget’s
progress is also printed both to stderr and feeds/FEED/encs.log.
Of course you can download only single feed’s enclosures:
$ cmd/encs path/to/FEED [optional overriden destination directory]