Thank you for the honest feedback and for providing the screenshots, Broken0_0!
The resource usage you are seeing is due to the underlying architecture. Obsidian Halo is built on WebView2 (Chromium) to allow for complete HTML/CSS customizability. Because of this, it has a higher baseline overhead than native C++ applications like Wallpaper Engine. Running real-time JavaScript loops for things like the Audio Visualizer and Particle Engine will definitely use a chunk of CPU/GPU, especially depending on your hardware specs and the number of monitors connected.
If you want to lower the footprint while using Obsidian Halo, I recommend turning off the Audio Visualizer, and disabling the Atmospheric Particles in the settings, as those are the heaviest real-time processes.
I am always looking for ways to optimize the JavaScript rendering loop, but it will always be a bit heavier than a native shader engine. Thank you so much for giving it a try!