@Staudey, Yes, I realized that it was old at some point, but just didn't really know what else to try.
The flatpak version works with no issues so far, except for the oddity that it changes the mouse cursor to the (default?) black breeze. But that's okay.
@WetGeek, I use Franz as a one stop shop for most of my comm needs: email(s), whatsapp, todoist etc. Telegram is also supported, as are many other services. Pretty convenient.