Backup 128GB NVME to USB flashdrive?

I'm looking to backup my OMV OS that's sitting in a 128GB NVME to a USB drive.

I've tried to use Clonezilla to clone the NVME to the USB. Clonezilla is able to clone the image to the USB without problems -- image is way less than 16GB. I tried restoring the same image on a Virtualbox and Laptop and the Clonezilla restore process finishes and after I reboot it says that there's no OS installed.

I get two warnings during the Clonezilla restore (see attached images) and I don't know if that's what's preventing the restore or if it is caused by the fact that the USB needs to be the same size.

So, my question is: is there a way to back up the 128GB NVME to the 16GB USB or do I NEED a 128GB external SSD/USB/HDD?

Thanks in advance for the responses.

Quote from macom

Sorry, but your post is confusing. You are talking about backup and restore. Maybe you should describe what you have done and what you want to achieve.

As you got a warning from Clonezilla, what did it say?

Confusing is an understatement. I couldn't even understand what I wrote. There were missing sentences for some reason.

I've edited the original post, hopefully it's more clear.