But we would have no idea on whether you want your config file to be placed in working dir or /etc/gotify/, also I cannot predict whether you might want to use environment variables for configuration.

But I think we can include a default config in the release package, so when you decompress the archive the config file is extracted as well.

I propose to create it in the same directory where the gotify "data/" folder which its subfolders is created. So all relevant folders, datas and configs are in the same place.

(When you create an official *.deb file then you can place the config file in "/etc/gotify".)

Having a sample config file in the release package would be a "quick win". Good idea.

I still prefer my solution.
The data directory does not necessarily exist: current references to that directory are only in the default configuration and user might want to override that.

I agree with @eternal-flame-AD, lets include a default-config.yml in the zip.