I believe you had a bad experience, but i would suggest the blame lays on your package maintainer - in debian (and ubuntu), ksplashqml should be part of the plasma-workspace package, which you can't avoid. What distro were you using?
Is it possible that ksplashqml was really present, and actually the "not found" error was because ksplashqml could not find a custom splash theme file? Had you installed and removed any custom themes?
Sorry, just wanted to test-drive KDE without wiping my entire system. My friend even had this problem on KDE Neon.