DirectAdmin Multi Server Setup only does only one thing:
It allows you to automatically run DNS on multiple servers.
It does that well as long as all your DNS servers are running DirectAdmin.
If you're looking for a Master/Slave DNS solution including slave servers not running DirectAdmin then you might want to look at Master2Slave DNS Replicator; you can search for it in these forums.
If you want to control other resources within DirectAdmin on a multi-server level ... well then you're just out of luck.
So as far as I understand, for each server you need a seperate license and CONTROL panel. Unlike helm3 or 4 or plesk, It does not support multi server management. It is too bad, I have just decided to buy and use it. Now I have to think again.