I had a really frustrating time when I was trying to have a SATA and m.2 drive. Turns out some sata ports cannot be used while an SSD is in a given m.2 slot.
Look up your motherboards instruction manual, it should have the rules listed out. Give them to chatgpt and ask it to tell you how to plug your drives in.
For your education:
Pacman like many other package managers tries to minimize network queries, to do this you download a manifest of every package available and its installation instructions.
-Sy
downloads the latest manifest from all of your pacman repos,-u
installs the packages whose “version” field changed between the old and new manifests.These error messages show that the domain name the manifest had for your package was unavailable, this is why you should check for updates.