How to install Windows 7 (ISO) on MacBook? in 2020

Hi,

I want to install Windows 7 on my MacBook Air running MacOS Catalina. I know this is quite the challenge but I love the OS too much not to give it a try. I have an ISO file for Windows 7 64-bit that I downloaded. I installed Windows 7 using that ISO in a virtual machine (Virtual Box), but I decided I want to Install it to run on its own. Now I know that the ISO file is working at least.

Installing the software using Bootcamp assistant is not an option unfortunately, since Bootcamp on MacOS Catalina only supports installations of Windows 10. I also want to allocate more than half of my SSD space to Windows wich bootcamp also dosen't allow on a 128gb Mac. Since Bootcamp is not an option I researched how to install Windows 7 using a different method.

Most tutorials instructed to first partition the disk using disk utility, then open the ISO file and copy all contents onto a formatted USB stick. This USB stick should then be bootable. This did not work for me, nor did any program I tried. When restarting the Mac, holding down option and r, only the Maciontash disk shows up and can be booted into. After hours of trying, I downloaded a Windows 10 ISO file, and voila, I could boot into the setup screen. Why does it not work with the Windows 7 ISO? The ISO worked in Virtual Box? Anything else I could try?

Any help and/or suggestions are much appreciated!!!