Kali Linux bootable USB not showing up in boot menu I am using a 2018 MBA running Big Sur
I wanted to create a persistent bootable USB with Kali Linux and have followed the exact instructions as given in this article: https://medium.com/macoclock/install-kali-linux-live-usb-with-persistence-using-macos-b1574c996491
However after powering on and pressing the option key, the bootable USB does not show up. This is partition containing the OS:

Here, it shows Bootable &quot;No&quot; but I don't know why. Also this partition is not mounted and Big Sur isn't allowing me to mount it as well and shows an error.

I am not sure what the issue is here and would be extremely grateful if someone helped out
If my memory serves me correctly, you can not boot iso9660 images from a partition on Intel Mac computers. At least not directly from the Mac firmware. I am not sure what the author of your linked reference was thinking.
I would recommend following the instructions publish by kali.org. Below are two webpages which together cover the creation of a portable Kali with persistence.
Making a Kali Bootable USB Drive (macOS/OS X)
Adding Persistence to a Kali Linux &quot;Live&quot; USB Drive
If you are still having problems, then update your question and post a comment below.