Matrix - synapse obviously still needs a lot of development. If you search for matrix synapse admin panel you will find a lot of hits.
On github someone has started to develop an admin interface: https://github.com/aminhusni/Trinity_Matrix_Management_GUI
Maybe this is a start? Otherwise I understand you are stuck at commandline db management. Although the recommended way to manage users and rooms is through the API.
Here some documentation on the API: https://github.com/matrix-org/synapse/tree/master/docs/admin_api