I doubt it because delta lake is a file format. An optimized file format but a file format nonetheless.
For optimized writes to a RDBMS you also need a compute system which opens a connection and runs a driver. That is where the optimization could take place.
This supposed driver could leverage delta lake optimizations.
But I doubt that this is a high priority for Databricks. They are promoting the lakehouse architecture.
It is possible that they are working on optimized drivers to certain databases, but developing optimized drivers for many rdbms systems? Doubt it.