RebornOS has made a new plasma-meta file to remove Discover. In addition, it has updated its rebornos-cosmic-kde package.
We will have to wait for the files to propagate. Once the system is updated, you can simply remove Discover from the terminal with:
sudo pacman -R discover
You will be advised that Discover is an optional plasma dependency. Continue with the uninstallation. Restart your systems, and Discover will no longer be there.
This change only works with RebornOS, or with any Arch Linux derivatives that our repository has in the first place, as we modified an Arch Linux file (plasma-meta) in order to remove Discover.
Those users who want to use Discover will only have to install it, since it is not blocked.
The RebornOS Team