Generally when it takes so long for Windows to shut down is because it is waiting for a program to finish doing its operation when it was shut down.
You can try and see which program is causing Windows from shutting down normally. It might be a program running a scan or a background service is not shutting down as it should, a driver, or even hardware issues, etc.
From this Tech site:
Windows can take longer than usual to shut down when services, background processes, drivers or applications prevent it from shutting down normally. Diagnose and solve a shutdown issue by viewing running processes in Task Manager, clean-booting your laptop or starting Windows in safe mode.
It gives several reason for why it takes Windows so long to shut down and its fixes.