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.

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.