For me radarr and sonarr picked up my changed password no problem.
The steps I took were:
-Edited the binhex/arch-qbittorrentvpn container: Changed the Repository field to binhex/arch-qbittorrentvpn:4.6.0-1-01 and applied the changes.
-Successfully downloaded and started the older version.
-Logged in using 'admin' and 'adminadmin'. In Settings > WebUI, added a new user, replacing the admin account, and saved the changes.
-Edited the binhex/arch-qbittorrentvpn container again: Changed the Repository field back to binhex/arch-qbittorrentvpn and applied the changes.
-Updated Sonarr and Radarr with the new username and password accordingly.
Another option would be to whitelist 172.17.0.0/24 if you're comfortable with that.
