I can report the same issues as did AMBTL user. Transfering a folder with many small files takes much longer than with other FTP client. Also queue shows one file being transferring. WinSCP version is 5.10.2 build 7621
Thanks for your report.
The same answer: Can you please start a new thread and post a log file using WinSCP 5.10? And maybe a screenshot or two?