Inserting LOB data might be very slow
The cause might be that the network communication bandwidth between the client application machine and the database server machine is too limited.
The larger the LOB data that you are trying to insert, the more likely the performance is to be restricted by limited network communication bandwidth.
Diagnosing the problem
Try running the client application on the database server machine, or on a machine that has a greater bandwidth connection to the database server machine.
If that makes it go faster, then that is a sign that what was causing the inserts to be slow is limited network communication bandwidth.
Use a tool such as iperf to measure the network communication bandwidth.
Resolving the problem
Increase the network communication bandwidth between the client application and the database server.