This rehashing issue has existed for several years and persists today. The joplin server start command serves as an API server, similar to the terminal app, and they are not suggested to run in the same profile so that it is certified that they should coequally have independent data sources and relevant synchronization. So why not add periodic sync to the server usage?
BTW, if I'm correct, Joplin Server and the server argument of the Joplin terminal app are different, even though they seem semantically identical.