I want to control which websites I can access every hour.

I'm sorry for the rough question, but I appreciate your cooperation.

I would appreciate it if you could give me an idea like this.
On the school network, each classroom has 30 PCs and 10 classes.
I'd like to limit the number of sites students can access through a web browser from time to time for each classroom.

For example,

• Make Facebook and YouTube inaccessible during class
• During the break time, you can also access the following sites:
• The classes to be tested should only be accessible to testing websites to prevent cheating.

I would like to do that.

Both clients have Windows 10 Enterprise installed.
On-premise Windows Server 2016 is used to manage clients with AcriveDirectory, DNS, and DHCP.
I don't use VLANs now, but they are available.
(All 10 classes have the same network, but VLANs can be class-specific.)
The router connected to the public network is the Yamaha RTX 1210

As for my idea,

• Set up a proxy server in each classroom and control it there.
• I don't know if it's possible, but limit your DNS servers to make them inaccessible.
• Set conditions in the router IP filter.

I can't spend much money, but I would appreciate it if you could let me know if there is any other easier way.