User logs on captive portal

[baneagle]

Hi there,

I'm trying to create a captive portal for a guest Wifi.
The portal is working fine but I need logs containing the username next to the website.

I understand I can do that with a proxy but obviously, I can't install my own AC on personal devices if I use a transparent proxy.
I've heard about Zenarmor too but I have 0€ budget for this project. We agree I can't use it for up to 254 devices with a free version?

Does anyone have an idea how to achieve this?

Thank you for any tip you could give me!  :D