You should be able to add Windows to the grub bootloader by simply updating grub from antergos. I'm using a similar setup with Windows and Antergos on separate disks. If you think 800MB is small for memory usage you can go even smaller with super lightweight DEs (like LXDE and i3) so you can use a system with less than 1GB of RAM, if you can even find such a system these days. Alternatively can try to match windows' memory usage with flashy DEs (like KDE and Cinnamon). I use XFCE since it has a nice balance of flashy features and low memory usage. Regarding Photoshop and Illustrator, there is GIMP, Inkscape, and Krita that are similar but may not do everything you want. There is blender too but that is more focused on rendering and animation. Can't help you with inDesign as I never used it. Games are hit or miss and that is primary reason I still have Windows. Wine works often and requires at least a little effort but I'd rather play the game written for Windows in a Windows environment. Work arounds like qemu are just painting over a hole in the wall. Welcome to the world of linux
My approach has always been to partition the disk first, then install windows on one partition(if not already installed) then install linux on the second. This way grub will be set up and will find your windows install and add it to its list of things it can boot into. I also use separate disks for each and just select the disk (thus O/S) during the POST process. If you want to stay in linux you can use a windows virtual machine with virtual box. You can download a Windows ISO and try it out without paying for activation to see how it suits you. As for why things are so complicated and not user friendly? Well that's basically Linux.
I've encountered a problem formatting a new disk when upgrading my laptop from HDD to SSD. I came across MiniTool Partition Wizard (Free version specs here) which is now my go to tool for creating partitions and formatting disks. resizing partitions on the fly and even switching from GPT and MBR is stupidly simple using it.
At the risk of making an arse out of myself, doesn't Krita support the CMYK color model or is it converting like most seem to do?
