I had a hard time setting up the new sync server for Firefox which is written in Rust because the documentation is very bad.
After a lot of try and error and reading comments of people in the issue tracker I finally was able to set it up and run it successfully.
Mostly for my future self, but perhaps it also helps other people I documented it with help of a README and a docker-compose.yaml which makes it easy for me to upgrade if necessary and also to store all the other config files with examples.