Unfortunately, Acast doesn't support any prefix URLs.
Most other hosting providers do support adding prefix URLs. That's why we're hopeful Acast will soon be able to answer all of our requests.
What you can do in the mean time is contact them via email (firstname.lastname@example.org) and ask them the following:
Message to send:
I've noticed that Acast currently doesn't support adding the URL prefix of Podder Insights (podderapp.com).
May I ask if there is some workaround that we can do so I can use their services?