This is my Thinkpad T410 with a 1st generation Intel Core i5 and 8 GB of RAM. It runs Arch Linux with Xfce.
The macOS Mojave (chosen over Catalina or Big Sur for it’s lower resource usage) VM works surprisingly well with 3GB RAM, but even when the Windows VM was allocated that much, it was very sluggish.
The Windows installation was very easy. All you have to do is download the ISO from Microsoft, and fill in your username, password, and product key in the “Express Installation” feature of Gnome Boxes.
For MacOS, you can use the excellent scripts by foxlet to automatically download the image from Apple and provision a QEMU virtual machine. The installation will take some time. Once you have installed macOS using the onscreen menus, you need to select the fourth option in the Clover Bootloader, Boot macOS from x. The first option will boot the install media again. I didn’t take screenshots of the install process.
If you want me to write more about this, contact me!