Simon,
Looking at the contents of the RSS feed for https://rss.art19.com/techmeme-ridehome there does not appear to be a link in the XML.
I compared a “working” feed with the art19.com feed and found the only URL was the <enclosure url="https://rss.art19.com/episodes/f54ad305-b10d-4842-abb6-e01908b82e74.mp3" type="audio/mpeg" length="3282651" /> URL for the podcast audio.
Compared with the “working” feed <link>https://play.acast.com/s/myfirstmillion/suliali-frommaking-76kjobatmicrosofttosellingtinycofor-100m-</link>
Therefore if this plugin requires that link then the https://rss.art19.com/techmeme-ridehome feed will not work.
cheers,