Fontsource has a lot of the same fonts as google fonts (and a few extras like Iosevka). Keep in mind that they do not offer a CDN which means that to use the font in your project you must host it yourself.

playerctl can list and control (most) media players individually, and would be suitable for writing a script with. In terms of rebinding keys you might be able to set them to run shell commands using global shortcuts in KDE system settings, although I’m not at my computer right now to test it.