Ubuntu – Anki does not run on Ubuntu Budgie 18.10

When I start Anki on Ubuntu Budgie 18.10 I get the following two messages:

1. Qt version issue You are using Qt version 5.11.1. Anki has only been tested upstream with version Qt 5.9.x. Upstream suggests only
   using version Qt 5.9.x, and a standalone version containing the
   required libraries can be downloaded from the Anki website.
   Continuing with this Debian version could potentially lead to loss of
   data (though this is unlikely). Are you sure you want to continue?

and

2. Fehler beim Start: Traceback (most recent call last): File "/usr/share/anki/aqt/main.py", line 50, in init
   self.setupUI() File "/usr/share/anki/aqt/main.py", line 75, in setupUI
   self.setupMainWindow() File "/usr/share/anki/aqt/main.py", line 585, in setupMainWindow
   tweb = self.toolbarWeb = aqt.webview.AnkiWebView() File "/usr/share/anki/aqt/webview.py", line 114, in init
   self.focusProxy().installEventFilter(self) AttributeError: 'NoneType' object has no attribute 'installEventFilter'

I installed Anki via the terminal with

sudo apt-get install anki

and apt-cache policy anki returns

anki:
Installiert: 2.1.0+dfsg-1
Installationskandidat: 2.1.0+dfsg-1
Versionstabelle:
*** 2.1.0+dfsg-1 500
500 http://de.archive.ubuntu.com/ubuntu cosmic/universe amd64 Packages
500 http://de.archive.ubuntu.com/ubuntu cosmic/universe i386 Packages
100 /var/lib/dpkg/status