Installing Linux and WiFi support

I have tried to install Linux (Elementary OS) on both macOS and Windows; and number one impediment? -- the lack of WiFi.

Of course, there is an official troubleshooting here.

Installing Linux on macOS MacBook Air -- Major Obstacles

Installing Linux is never hard on Windows, with supported hardwares, e.g. Dell, but on macOS, it is another beast; probably because of a very specific proprietary hardware -- main harddisk and cannot install additional internal harddisk. Furthermore, I have both macOS 11" (2015) ad 13" (2017) with different problems. After, it is never as easy as installing Windows.