If the external HDD is not converted as Internal Storage for the TV, do note that most of the Android TVs do not have Write permissions for external storage devices. So, in that case you won't be able to transfer using TV.
Install any file manager which can the FTP protocol. Solid Explorer, MiXplorer, Total Commander + FTP plugin, X-Plore.
You can use "Send files to TV". However if its a big file, it will take time.
Quit pirating shit on mobile?
Just use an OTG adapter, that's it.