How to restrict wifi access on a certain laptop during the daytime.

I'm not sure how to do it in any case, but it would help to know what OS is running on the laptop, what is being used as the Wireless Access Point (to which the laptop connects; may be your modem/router), and what is the DHCP server (may be your modem/router).  Those are three different points where this might be enforceable.

Windows 10 and or Windows 11

Most routers can be setup to block certain MAC addresses from using it at certain times (often it is called something similar to "Parental Care" or similar. You of course must make sure the user of that PC doesn't know how to login to the router & change settings, & it should also be at an unreachable place so he can't do a hard-reset of the router.

That's a good start.  "what is being used as the Wireless Access Point (to which the laptop connects; may be your modem/router), and what is the DHCP server (may be your modem/router)"

This is called "Doin' It the Hard Way."

1.  Write a Powershell script to stop, then disable the WiFi service if it is 7 AM or later but before 1 PM, and enable, then start the WiFi service if it is 1 PM or later but before 7 AM.
2.  Make this script a boot-time Scheduled Task which will take care of startup.
3.  Make this script a system Scheduled Task to run at one minute after 1 PM.
4.  Make this script a system Scheduled Task to run at one minute after 7 AM.

This will deal with any user without Administrator privileges.

Another way might be using an antivirus to block internet access at that time and allow internet access the rest of the time.

what if they use another router?  (hotspot?)

@Hello There - interesting suggestion - do you know of an antivirus product that can do this? I'd be interested ;)