Comment # 2 on bug 1157504 from Jai Seok Ahn

(In reply to Stefan Br�ns from comment #1)
> Cura "allows" to connect to an Ultimaker account.
> 
> When there is no authentication data (e.g. on first start, or when the user
> just does not want to use an Ultimaker account), the account handling code
> returns a python "None" object (with an account, it would return a "dict").
> 
> Later, some Qt slot handler tries to convert the None object to a
> QVariantMap, which fails.
> 
> 
> Can you try with the package from:
> https://download.opensuse.org/repositories/home:/StefanBruens:/branches:/KDE:
> /Qt:/5.13/

I installed and replaced with python-qt5, python2-qt5, and python3-qt5 (version
5.13.1-158.8) from the above repo, and Cura starts and works now.
It goes with a bit low-resolution graphics mode to me, but I can handle it.