Telegram-desktop client and voice calls

I’ve install the telegram-desktop app and after installing also qtwayland5 it fits very nicely to the L5 screen. One can even do voice calls to other tg contacts.

The problem is, that in the L5 the audio comes out through the speakers below and I do not see how to configure or change this. Any idea?

You can temporarily change the output under System Settings -> Sound -> Output -> Output Device (Handset), but I don’t think there’s a way to have telegram audio always come out of it