Android phone reset but not showing in my list of devices

Help - I had to have a factory reset on my phone. I had most of the avast software installed on my phone and it was successfully updating and backing up to my account. So after the phone was factory reset I assumed by reinstalling the software and linking to my avast account I assuming it would link to my existing device. So I installed AV followed by anti theft and then backup and soon on. My password vault synced ok however when I looked at my account I had another device listed . The backup app was also working ok by had linked itself to this new device. But the anti theft and av was not working correctly. Although it seem to say installed it could not connect to the device. I even went back to my old device and that won’t connect to my device either. So I uninstalled the av, backup and anti theft apps and deleted the new device from my account. I only reinstalled the av. however, it is not showing up in my device list. I don’t want to delete my old device , as I want to restore some of the details from that device, if I cannot linked it back. So help. Can I relink my device back with my existing device on my account ? if not how can I get a new device listed on my account with my old device still listed? I’ve left this a few hours with just the av installed but it’s still not showing in my list of devices and my old device cannot connect still either. Any help would be appreciated. Txs

did you ever figure this out, i have the same issue