This is a modified version of mediacontroller plasma5 widget.
It provides the same functionality as the traditional mediacontroller widget, giving you control over every media player in your system (through the MPRIS2 protocol), but it adapts to more factor forms and sizes, allowing you to have a nice media control even on the panel.
You can download it on the KDE Store, or use the built-in 'Get New Addons' directly in your plasma desktop.
Full Representation (desktop, pop-up):
Compact Representation (panel, systray):
Different Views:
Minimum (preferred) / Maximum widths configurable
Display options to show/hide progressbar
Drag and drop any media file or URL to open it
As a disclaimer, it is one of my first tries on qml and plasmoids, and I just wanted to have a nicer media player applet for my panel, while keeping the most of the classic widget untouched. Of course, my main wish would be for this changes to be integrated in the official mediacontroller applet, which I find kind of visually simple in its current state.