Bitwarden and Riseup VPN
Bitwarden app failed to sync with its servers while Riseup VPN was running. This behavior is unique to Riseup VPN (I've tried other VPNs such as Mullvad, they don't cause any issues). However, bitwarden.com is working just fine in the browser.
This could be an issue with Bitwarden as well. I've also contacted them.