How speed up mysql dump without data?
File creation is the main part of the sluggishness, especially on Windows.  So, decreasing the number of files is key to speeding up your process.

Each MyISAM table needs 3 files.  Each InnoDB table needs 1 or 2 files.  Switch to InnoDB if not already using it.

Each PARTITION is a "table", so it counts as above.  More than about 50 partitions is inefficient, and this is one of the reasons.

Having more than a thousand tables is usually (not always) a sign of a poorly designed schema.

VIEWs, TRIGGERs, Stored routines, etc each take at least one file.

Parallel loading may or may not help; it depends on whether the OS can create multiple files in parallel.