thank you for an idea. It depends on SQL DB you'd like to use. We have some long term task to support a GeoPackage format. It's a modern format, basically based on the SQL database. So maybe would be better to support the Geopackage.
BTW the project database (/LocusGIS/projects/project_name/project_name.db) is standard .spatialite Database and some users uses this database to share data between LocusGIS and desktop
We use mariaDB as our main db for all our staff. Our usecase will be a sharing between our software-solution and Locus GIS >> so when our staff in the offices set one order in the software the staff on site should see that within the SQL-Layer, and also the way back, when the staff on site change status (for example from "pipe in the house" to "pressure-test completet") the staff in the office should see this also... I think its a very simple SQL work, and with SQL we will be very flexible in the communication between the software on site and in our office. Also there is no offline version needed, case you are you online, you will see the layer, case not, you will see maybe old stuff, but it should be only editable when online. We can also talk about costs, case it helps :) But I think with this feature, the software will be more flexible in a known way...
So what you need is real-time database connection to your server with MariaDB, am I right? I'm sorry but this feature isn't planned at this moment. What already thought about is connection to PostgreSQL- PostGIS database that's more common in "GIS world". However, our long-term intention is to support WFS-T that would bring possibility of real-time edit of vector geometries that are stored on the server side