I'm trying to set this up as to get my Docker container to communicate with an existing database in the server, I've tried opening it out, setting up so that it's know in the .env file and even tried the settings on the compose file, but couldn't manage to make it work.

Other tries:
mysql://{my_actual_server_ip}/n8n // with and without user:password@...
mariadb://{my_actual_server_ip}/n8n // with and without user:password@...
http://{my_actual_server_ip}
I'm trying to install n8n, and it works fine, but for ease of management and backups, I'd like it's DB to be manage through Databases, as are all of the other I'm currently running.