I had the same problem and finally decided to uninstall the Epic Launcher and reinstall it. Downloaded all my versions of Unreal Engine…5.3…5.4…5.5. Then I was able to install Quixel Bridge to all versions…Then searched for Metahuman Plugin found it in my vault …installed to engine…selected it in my plugins and restarted…Lo and behold there was my Metahuman Animator