I built something which may be able to help: https://github.com/dmuth/grafana-playground

You'll want to spin this up in Docker Compose, and to add custom hosts upstream of you (such as ISP routers), you can edit the hosts.txt file (to add in human-friendly names such as "upstream") and add those hosts in the HOSTS variable in the docker-compose.yml file.

Feel free to open an issue on the project or reach out privately if you have any questions.