I typed "Zulip docker compose" into DuckDuckGo, the first result was https://github.com/zulip/docker-zulip which has commits from today, so doesn't seem out-of-date.
> Had to use ChatGPT to help generate me a docker-compose.yml, except it forgot about memcached, set the wrong environment variables and just generally did a sloppy job.
It has a docker-compose file in it, has memcached in it.
That's very understandably annoying. If can you confirm that that is what happens, a bug report either with Zulip or ReadTheDocs (not sure which) might be in order.