I use ARCH btw

Following the guide is mostly ok ;

- no need to partition if there's no need to (esp EFI) ; you'll run into a permissions nightmare on your /home, but that's better than loosing data - only format your system / partition (or root partition) with makefs.<type of filesystem> - it's ok to mount the EFI partition to /boot/efi so as to not fill that small partition with everything in /boot, especially numerous kernels

- default install through pacstrap needs a lot more stuff, you'll probably want: -- base-devel linux-lts os-prober pacman-contrib -- grep rsync snapper nano tar git -- gdm gnome networkmamager gedit -- bluez bluez-utils -- firefox vlc smplayer gimp

When you chroot in, it's normal for os-prober to not see the M$ partition, even if it is mounted ; you should re-run it, and grub-mkconfig, when you did reboot into the actual system

- don't forget to start some services, duh... -- gdm.service -- NetworkManager.service -- bluetooth.service with systemctl enable --now <name of unit>.service

Create a basic user with

   useradd -m <name of user>

Add it to sudoers with

   EDITOR=nano visudo

Now you can reboot. Have you installed some network software ? Have you started a graphic shell ? That's tje core needs for a functional fresh install to be tuned further as needed.

Set up aur or flatpak for dropbox and ungoogled-chromium ; add python-gpgme for dropbox