Giving 2017 Mac away. Erased hard drive. Recovery says error installing OS Sierra. Help!

I am preparing to give away a 2017 iMac Retina 4K 21.5-inch. After erasing it in Recovery Mode using Disk Utility, I cannot reinstall the OS (Sierra), which stalls at 16 seconds from completion. I have attempted repair using First Aid in Disk Utility, including following these steps:

How to repair a Mac disk with Disk Utility - Apple Support

I performed First Aid on the two HDs listed in the left column: There were two HDs in my list, and here is why--

Two years after buying it in 2017, service replaced the Hard Drive (still under warranty). As a result, there were two hard drives visible on my desktop, HD and HD2. I always thought that was odd, but things were working so didn't pursue it further.

Now, after using Disk Utility to repair HD2 and remove the first HD, I cannot reinstall the OS, which is in this case Sierra. In an earlier attempt, it was Monterey. So I don't know what is going on.

Here are the screen shots of my error report, and the Repair work I performed with First Aid.

Of course I tried this several times, including on both HD and HD2 before I performed First Aid on them.

After I repaired HD2, and renamed it Macintosh HD per instructions.

This appears to be the original HD, but I don't know for sure.

Can anyone help? I'd like to put an OS on this machine so it can still be used.

Thank you.