You compositor is turned off, that is why your visual effects are not working. Search "turn compositor on KDE" for the method to restore animations, transparency, etc.
Generally, unless you know what your doing you should avoid dual/multi booting. The inexperienced are almost always going to experience issues at some point. Unfortunately, Garuda can't officially support multi-boot complications. If you choose to install in that manner it's your responsibility to learn how to fix your own system.
If some kind member chooses to assist you that's great. However, don't count on getting assistance if you go down this road.
Welcome to Garuda, and I hope you get your issue resolved.