is there a way to copy a Time Machine disk to a 2nd disk?

Is creating a partition archive via Disk Utility and restoring it really a good idea?

Although, it is technically possible, it’s not ideal. When you use Disk Utility to create a partition image (like a .dmg or .sparsebundle) and restore it to another drive, you’re essentially doing a full sector-level clone. This means you have to:

• Clone the entire partition the Time Machine backups reside on, not just the folder.
• Ensure the target drive has an identical or larger partition to receive the restored image.
• Be aware that this method is often slower and can fail silently if there’s any corruption or hiccups in the image or drive format.

This approach is typically used for migrating bootable drives or full system volumes—not really for handling Time Machine backup volumes, which are managed differently by macOS.

The OP may be better off using a third-party solutions, like either Carbon Copy Cloner or SuperDuper! ... but, even these come with a risk. The best solution is the one John Galt has proposed and that is to use a second drive for TM backups. Simple and easy!

No, we can't do that any more.

Having at least two, separate, independent, redundant Time Machine backup drives, with at least one of them kept geographically separate from all others at all times is a very good idea though.

Time Machine will back up to as many of them as you wish to provide.

That's not so. We LOVE helping people.

As I wrote, we simply cannot copy TM backups from one drive / partition / volume to another any longer. We cannot use DU restore, asr restore, cp, ditto, Finder file copy, third party utilities including Carbon Copy Cloner or SuperDuper or anything else to accomplish that. It won't work. I have tried. So have many others.

It used to be possible in the distant past. Apple even provided the instructions. Those instructions were silently removed following the introduction of APFS and Time Machine's concurrent adaptation of it.

In other words,

scutoid wrote:

Create an partition archive using Disk Utility, and then restore it onto another drive

... will not work for Time Machine backup volumes.

Not the case at all. You're new here ... so welcome! I've been here awhile, and trust me, a number of times in the past, I have provided advice that was either not 100% accurate or just flat-out wrong ... and, when I do, fellow members chime in to provide me (& more importantly to the OP) with a path to a better solution, but they also guide/teach me with where I went astray with what I offered. That's why it's a "community" and not just a forum. We help each other. I was only trying to do the same for you. If you decide to stay with us, great! I look forward to "working" with you.

Create an partition archive using Disk Utility, and then restore it onto another drive

As already stated, no.

You LOVE to try proving people wrong