Hello,
It is often recommended that you use latest version of Windows. V2004 is the current latest version.
You can try upgrading to V2004 via ISO file, which is one of the best way to upgrade:
Refer this step-by-step guide:
https://www.kapilarya.com/how-to-upgrade-to-windows-10-using-iso-file
The time taken to complete upgrade is not fixed and completely depends upon your system resources.
Don't worry, if you face some issues with V2004, you can downgrade back to previous version within 10 days after upgrade.
Regards.
Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.