other Approachs to install Linuxcnc

Yes this is also possible (dd is your friend)
You can also put the boot image on a hard drive. I did that a long time ago it’s the same process for a usb disc and a hard drive when using a Linux machine. Even with Mac it should be the same.

Clonezilla is an option, but an initial install is still required & if you can't boot the target system via cd\dvd\usb you still need to do everything on a 2nd machine. And for a one it's a lot of work, far more than doing an install and transferring the drive from one machine to another.

I know I just wanted to say it is possible.
If I can’t boot from USB but have access to the hard drive I would install it on another computer and move the HD or make a 2nd hard drive with the install media.

But If I have another machine already running Linuxcnc and want to clone everything I would give DD a chance
Cause remembering alle packages I need to install later and compiling come other stuff, failing installing other packages trying again, also takes time

Clonezilla is a hell of a lot quicker than using dd.

You can do a disc to disc clone. Doing it this way doesn't give you a image you can backup.
A disc to image then to disc clone. This way does give you an image you can use multiple times.

Maybe I am to old scool here. I was a regular Linux user 15 years ago the I switched to mac and stopped playing around with computers (had something to do with getting a job).
It was when I started using LinuxCNC four years ago i used Linux again. But only for my CNC. I am happy many of the old stuff still works.

Why not use balena etcher, that is cross platform.
I do lots of different iso to sd/ssd. Never had a non booting that way.
m5c.
Mike