Voicemail doesn't function properly

Has anyone else ever had an issue where they can’t see when they get voicemails? Not only do I not have Visual Voicemail (or an option to set it up), I don't even get any sort of numerical notification that I've got a message (which is how things worked before Visual Voicemail existed, if I recall). I have to actually call my voicemail to find out IF I have any messages, and then sit there and listen to the robotic voice read out every detail before even getting to hear the message, like it's 2009. Heck, even home answering machines had flashing lights that told you if you had messages or not... I currently have 8 new voicemail messages, but you'd never know it without actually calling voicemail and putting in the password - see screenshot.

I’ve already tried restarting (duh), Reset Network Settings and Reset All Settings. I’ve been on calls with both Apple and my carrier, Spectrum, to no avail. (Side note that may or may not be relevant: Spectrum is not listed as supporting Visual Voicemail on the Apple website, but I'm on my boyfriend's plan and he DOES have Visual Voicemail. He transferred his plan from Verizon so might be grandfathered in... however, Spectrum supposedly piggy-backs on Verizon's network so I wouldn't think that would be an issue and neither did Tech Support. Plus, I transferred from Verizon as well - although I changed my carrier AND my phone; he did not change phones.)

The last resort suggested by Apple is to do a total wipe/reset of my phone WITHOUT restoring anything from a backup. This is my SECOND iPhone 12 Pro Max because the first one had problems too, so this would be the THIRD time in two months I've taken the time to set up a phone because of these issues, so I'm not thrilled to waste several more hours doing that.