So, I am interested in really figuring out a way to use WPMS with different remote databases for each new sub-site added.
What I know. I know that a remote database can be on it's own server to allow remote site connections with the DB user's added privileges with IP binding to the DB as % (wildcard) or an IP address (if your servers are part of a network).
A quicker way for me would be to use GoPanel: https://gopanel.io/ It allows me to make and configure my MySQL databases on a Linux server.
And I have tried and tested with success doing this manually or, at least getting somewhat close using the plugin, Multi-DB (https://github.com/wpmudev/multi-db).
However, Multi-DB allows separating the create site's database BUT, ONLY within that single database server. However, I would like to make a database server for each new sub-site created.
So my plan of action would be to write a simple plugin with a few text fields (DB IP, DB User, DB Password) and have these fields show in the site options area of WPMS.
And so I am looking for directions on:
A) Location or hook to site options to add my fields.
B) Where and How I can change WordPress MS default logic on how sites are tied to the database/table after created. And replace them with my field options.