Voicemail disappeared after IOS 17.4 update

I hadn't done an update in a while because it seems like there are always issues. But I was unable to update several apps because of my old IOS version so on Sunday I broke down and did the update. To my shock, ALL of my voicemails were gone. I read a bunch of community notes on it and tried a number of things people said worked for them. None of them worked for me. I called Apple Support and a really nice guy spent about an hour on the phone with me. The end result was that he said Apple acknowledged there was an issue and were working on it. No idea on the time frame. He suggested I call my carrier, who said they don't have them because they should be on my phone. Well, they're not on my phone and like many people, I've lost voicemails from family members who have passed. I am devastated. I've tried turning off the visual voicemail and then restarting the phone. That didn't work. I called into the voicemail messages and they aren't there either. I'm a little hesitant to restore my phone from the last backup I did, 2 days before the update, but the Apple guy said that may work. Has anyone tried that or has anyone tried anything else to recover missing voicemails that worked? I figure they have to be somewhere. I'd appreciate any help anyone who experienced this can give. Thanks!