How do I set up a private network on an enterprise WPA2 one?

I am trying to connect my Google Home Mini and other smart devices to my university network.

Like most universities in the UK, mine uses eduroam. I have ethernet ports in my room, and a WPA2 Enterprise wireless network. I have managed to successfully connect an access point to it (just an old ISP provided router), and it provides a wireless network to devices around me, however, when connecting to the network on a phone or computer (on my private access point), a captive portal is presented, and I have to log in with my uni username and password. Once I have done this I have full internet access through the private AP, however this cannot be done on a Google Home.

Is there any possible way to avoid this, and just have a my private AP registered on the network, then use it as a bridge to just connect other devices to the network?

Thanks