I like to do things just off the top of the hour, since top of the hour is when many maintenance crons run. If you’re running a modern cron daemon, you can rewrite that as:

3 1-23/6 * * * docker container restart lemmy-lemmy-1

https://crontab.guru/#3_1/6_*_*_*

Doesn’t systemd have the ability to do this as well with unix sockets?

I don’t recommend using the shell on routers for day-to-day management. Instead, consider using a network configuration management system like rconfig. I’ve used RANCID in the past, but I suspect something more modern like rconfig will be useful to you.

I installed mine using the instructions here. I did run in to an issue with docker-compose, for which I submitted this pull request (assuming that PR is not merged by the time you clone the repo).