iPhone 8 plus not syncing to iTunes

I've been having this problem for a while now but have mostly been ignoring it. My 8 plus doesn't sync with iTunes. Meaning when I connect the iphone to my iMac, the phone says unlock phone for accessory mode, but the iPhone icon never pops up in iTunes. I've tried hard resetting my phone, my iMac, closing out iTunes and opening it back up again in every possible way with regards to connecting and disconnecting the iPhone. This all started after updating to OS Catalina and I'm completely up to date on every possible update. Am I missing something simple or is this just a one off situation that can't be resolved?