There is no reason whatsoever to install Etcher, or any unsigned app, or indeed anything at all - I’ve just confirmed that the inbuilt “dd” command works perfectly fine to boot Ubuntu on my mac:-
I have a Mac Ventura and it didn’t work for me either. I followed the instructions to a T. Was formating the USB instructions done correctly? I restarted my computer holding the option button - the USB never turned yellow nor showed.
Yes, the latest LTS version of Ubuntu Desktop (at this time Ubuntu 22.04.2 LTS) requires more than 4 GB. The ISO file for Ubuntu 22.04.2 LTS is 4,93 GB
Wanted to say thanks to the original writer for this document. Just used it to create a bootable USB on a Mac Mini m2 and it worked flawlessly for me. Thank you!