It’s not up to Garuda, it is up to the maintainer/developer.
But the upstream package had no development since a couple of years:
Also the packaging in Arch didn’t have much activity lately.
https://aur.archlinux.org/packages/plasma5-applets-window-appmenu
But I don’t think in this case (port to KDE6) they could do much.
That’s how distros work… Unless you can effort taking over the development, which is very different from integrating apps, or sometimes packaging them differently.