Associated Device Backup?

I lost my iPhone a few years ago and I did not know that there were options to recover anything from it. Now that I know, I would like to do just that.

The phone is still on my list of associated devices, but nothing from that device is in my cloud or account or anywhere that I can find, other than associated devices.

I have also requested a copy of my data, and I can see it there, but no data that was ever associated to it. Is there a way to do this? Is there a backup from the old device somewhere? My current backups only show my phone and my husband's phone.