Managing students wifi with data quota per month

So I’m a newbie at complex (IMO) router setups and have been doing extensive research both on this forum and watching some video tutorials. I have been unsuccessful in getting close to a comprehensive answer and would appreciate some assistance.

I have 14 students in a house with internet limited to 200GB for the month. I would like each student to be capped to 12GB per month after which their internet would run out until the next month.

I started messing around thinking it would be best if each has a separate SSID but have been unsuccessful in creating a quota per SSID. Most tutorials have shown me how to limit bandwidth but that is not my intention, I just want to limit total data upload and download for the month. I also want the quota to reset every month.

I also started looking at CapsMan and Radius but I was not sure whether these were necessary for what i am trying to do. They seem more suited to more complex setups for multiple routers and vouchers, etc.

I would really appreciate some assistance with this.

Thanks