I had very similar problems - I found the length of time for the first boot increases with the size of the card (so I'd expect that a 32GB card could be 15 minutes or more).
You mention you've got it connected on ethernet - look at the list of devices on your Windows IoT Dashboard. If you can see it there then you know it's working at least. I sometimes find that the first boot finishes with an error - after 15 minutes I got a CRITICAL_PROCESS_DIED error, but it automatically rebooted after that, and after a shorter period of time it took me to the Windows IoT set up screen.
I've posted about my experiences at the link below, but hopefully the information above is helpful to you given where you are in the installation process.
I hope this helps.