as subject. Thanks

Static IP of the device has been set (i.e. 192.168.88.20)

as subject. Thanks

Static IP of the device has been set (i.e. 192.168.88.20)

Use Kid Control. It's not very well named as it actually drives them crazy and out of control.

https://wiki.mikrotik.com/wiki/Manual:Kid-control

You can use Time under access list rule, never tried it, but should work.

You can use Time under access list rule, never tried it, but should work.

That won't work.
And the kid control feature as well.
They both can only restrict the hour ranges when the client can stay connect, not the total connected time per day.

You can use Time under access list rule, never tried it, but should work.

That won't work.
And the kid control feature as well.
They both can only restrict the hour ranges when the client can stay connect, not the total connected time per day.

True, there was some ambiguity to the question.

Hotspot might be easiest. If you want to only have selected devices use the hotspot you can add their MAC in the access list and force them onto a VLAN+bridge that runs the hotspot without needing to use a new SSID. Otherwise, just make a new SSID with the hotspot on it. Even then I don't know if on hotspot you can lock a device out when it's used up it's allocation for a 24H period. It might need some extra scripting to support this.

Set DHCP lease time to 24hrs

DHCP lease script add the host IP to a firewall list named "allowedLan" with a 2hr time out.

Firewall filter forward chain accept traffic from the src address list=allowedLan

Firewall filter forward chain drop traffic from the screen address list!=allowedLan

Set DHCP lease time to 24hrs

DHCP lease script add the host IP to a firewall list named "allowedLan" with a 2hr time out.

Firewall filter forward chain accept traffic from the src address list=allowedLan

Firewall filter forward chain drop traffic from the screen address list!=allowedLan

This is only good if the requirement is to start the clock from the moment the device is turned on. I think the OP needs to define the problem more succinctly.

Is it:

* 2 hours from device powerup?
* 2 hours of web browsing?
* 2 hours contiguous use?
* 2 hours accumulated over 24h rolling window?
* 2 hour window before kids bedtime?

Given most computing devices are on all the time and sleep and wake and do a DHCP request often the DHCP script might not be the solution.

The problem I do have with this, is that the kids uses internet on the cell phone if I turn of the Wifi.
Either their own phone or friend phone.

I did solved the similar task using the hotspot's trial period. A kid passes the captive portal without logging in and gets his/her trial time. You may change trial time by scripts (i.e. more for days off, less for weekdays). The trial record is removed at night. I don't have this device under my hands now, but I may look for a backup to publish here as a boiler-plate if need be.
However, now I need to couple the hotspot with kid control somehow to allow the kids to be connected by schedule (for the remote learning due to lockdown) plus some free surfing with a restriction of total connection time, as it was done before using a hotspot. At the moment I don't understand how to implement this...