@doodlemania2 it's nice to hear that it can be done, thx for the info. Maybe in the future it will be added as an "out-of-the-box" option, after all it is a fundamental part of Directus.
Stackhero(which is a service similar to Cloudron I believe) has it out of the box, I got Directus running on top of external db easily.
Directus has no feature to connect to external databases.
I am aware that English is not my first language, but unless there is a difference between external and remote database connection, I am sure that Directus can connect to external/remote database.