For the record rpm is not meant to be used on Solus like this. As the package description says:
The RPM Package Manager is provided in Solus to enable building RPM for RPM-based Linux distributions from Solus using tools like 'mock'. To build packages for Solus, use 'ypkg' and 'solbuild'.
In other words it is meant to be used to help package maintainers repackage things only provided as an RPM using our build tools to create an .eopkg as well for people who are packaging for distributions that do use RPM.
Using RPM to install packages on Solus is not supported and heavily discouraged, it can cause breakages for which Solus will not assist with.