Try removing the whole custom header from limine.conf and convert the CachyOS wallpaper to a background.jpg (not PNG) with 1920x1200 using Gimp.
Then add:
interface_resolution: 1920x1200
wallpaper_style: tiled
wallpaper: boot():/background.jpg
If that doesn’t help, we have different devices that react differently to Limine’s rendering process. It feels snappy (under 0,1 sec) on my mobile device, but apparently not on yours.
You can report the issue on the Limine Codeberg if you want the wallpaper to render faster
or just disable it for a plain black screen like systemd-boot if you are fine without a wallpaper.