P.S.: GPU and RAM usage is also concerning...
(Standard configuration, completely clean Windows 10 Pro. No apps or anything running in the background.)
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!