With the Mysterious Universe Android client being retired, we have to resort to third party podcast clients. The problem is that many of these have poor handling for at-signs in usernames, and as such generally fail at adding feeds that require login with e-mail and password. The solution is to import your subscription using the OPML format into your client, bypassing the need to escape any at-signs.
Here is a curated list of clients that should work for Android as well as the desktop:
This fom will help with generating .opml-files that can be used to import your subscription into various podcast clients. No information is saved on the server or processed in any way. If you are paranoid, leave the user/password fields empty and edit the downloaded file in notepad or other text editor afterwards. If you do, just make sure to replace the @ in your e-mail addresss with %40.
If you find any bugs or can't get things to work, poke noccy in the unofficial chat at #mysteriousuniverse:matrix.org on Matrix.
Feed:
E-mail address (username):
Password: