Add the --needed flag to the pacman command - this will only install missing packages
sudo pacman -Syu base-devel --needed
Even your system is fresh - there may be updates.
Do not sync new packages to your system without syncing installed packages as well.
VSCode is in the Archlinux repo and as such also a part of Manjaro official repo - and as you updated your system you can now skip the yu part
sudo pacman -S code
But if you want the Microsoft version you will need to use pamac to build the microsoft version. Pamac itself will install the necessary packages required to build a local package.