It’s not wrong, but it feels a bit like some tech articles you’ll see which are obviously just created to fluff up a CV. I wouldn’t say avyttring here is flat out wrong, just kinda… lacking.

But yeah, /boot holds “system boot loader files”, sure, but that’s a bit vague. It should contain your kernel and initramcpio and IIRC Grub also had its config here. That’s pretty much it. I would’ve rather said /boot contains the kernel.

“device files” it’s so vague that it’s almost wrong IMO. At first glaze I would’ve thought that it means drivers rather than, say, “interfaces to devices”

I don’t trust a graphic which explains /boot as “system boot loader files”…

This is the way. There is a GParted distro that you can boot from a USB-drive that will allow you to move the partition and expand it to take up the free space Windows left.

You should first install GParted to familiarise yourself a little with how the GUI looks. It’s relatively simple, definitely simpler than parted, but it doesn’t hurt to have a look around before doing it live.

It’s also good to note that everything you do in GParted needs to be applied before it’s actually done. You “cannot” accidentally delete a whole partition without actually hitting an apply button.