I've been having the same issue with my iPod Nano 6th gen with iTunes version 12.13.1.3 on Windows 11 Pro 23H2 (yes I know this is the iTunes for mac page.) I think this is some sort of transition from iTunes to the separate Apple music, Apple podcasts, Apple TV apps. I believe Apple is trying to back away from iTunes, both with buying songs and with syncing iPod. Like it or not, the iPod is coming close to it's 23rd birthday, and it's been more than a full year since it's discontinuation. I really hope that apple will still have a way of using iPods even if not integrated into the apple ecosystem, or at the very least I hope the community will make open source alternatives and music library managers with iPod support. My iPod does show up in the Apple Devices app, yet it only lets you configure some settings on the iPod, not sync it with any type of media. I also signed into the Apple music app on windows thinking then it would at least let me non-DRM music I put in the app. Unfortunately, Apple has no clear motivation as a company to come up with a solution because it wouldn't make them any money. Sorry that this wasn't really an answer or solution but I hope it brings light to this issues as us the customers that pay for all this stuff should be able to use it.
