Hello,
The ONT (HG8245W5) does not support filtering or blocking applications.
You can log in to the web page to configure parental control so that your child cannot access the Internet to play games.
The configuration procedure is as follows:
1. Click the Security tab, and choose Parental Control Configuration from the navigation tree on the left. In the pane on the right, configure different constraints for the network surfing time and website access on working days and holidays. In this way, their children are allowed to access networks in specified time segments and free from age-inappropriate contents.

Configure the template based on the target requirements.
2. Click Apply.
The HG, EG, DG, MA, and EA products are access network products.
Thanks