I have an application which uploads and reads files from another VPS (i.e. file server, Ubuntu 18.04). These servers are in the same network. The application (.NET core) uses SFTP protocol for files reading/writing.

For a 5 Mb file it takes 3 seconds to load a file, more than 2 seconds of which is the TTFB (80% of total time).

Is there a way to reduce the TTFB and accelerate file transfer/load?