I have some troubles with installing Shotcut and it is very similar to this one. However the provided solution does not work in my case.
Ubuntu 20.04.1 LTS (as returned by lsb_release -a but it is a fresh install of a XUbuntu distribution)
Shotcut 20.10.31 (with both snap and portable versions)
I have the following packages installed:
And I still have the error:
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.