Hello and welcome,
This is somehow expected, not quite normal, but since the device was probably prepared 3-4 month ago, with the preinstalled system, the mirrors that are currently defined can be out of sync.
A hint about system being a bit behind is the kernel version.
You can switch and refresh mirrors in Pamac UI Preferences
And then Refresh Database from the dropdown menu, or go via terminal:
sudo pacman-mirrors -f5 && sudo pacman -Syyu
or
sudo pacman-mirrors -f5 && pamac update
This should be helpful to learn more things about updates issues that can happen, with some explanations.