Chosen Solution
I have an iPod Touch 2nd generation I got second-hand, and restored it, and loaded music onto it. I recently decided to load a new playlist onto it, but after connecting it to iTunes and waiting a while, an error popped up saying “iTunes could not connect to the iPod touch “iPod” because an invalid response was received from the device.”. The only thing that’s changed from then to now is that I’ve updated to macOS Mojave. So, I tried recovery mode. It showed up in iTunes, and I restored it, but then it got stuck on the recovery mode screen, and putting it back into recovery mode and restoring it again did nothing. So, I connected it to a Windows PC, and it worked just fine, asking me to set up my iPod, and it worked. I then connected it ti my Mac again, and same error. So, at this point, I have an iPod Touch that can only be synced with Windows.
Try syncing the iPod on a Mac running High Sierra or lower. This might be a bug in Mojave if you can sync it with Windows.
