Easy actually. I’m on arch (Hyprland) right now, so no longer EOS but it’s been refreshing. I’d recommend EOS as a base for any arch install, better than “arch installer” by a long shot. If you have dedicated storage I’d recommend using it and booting to the respective system through EFI rather than relying on software bootloader (windows likes to break it). I am running arch on a dedicated SSD and it’s been smooth so far.
My recommendation would be to have Linux on the 500gb drive and then install windows directly on the other drive without partitioning. I wouldn’t install Linux on a partition as Windows likes to mess with the bootloader but if Linux is on it’s own drive you can always boot it from EFI without issues.