Yes, you're correct, @btks.
After you have signed in the first time opening the file in QBDT 2021 and updated it, you should be able to use QuickBooks without the internet connection. And when you upgrade QuickBooks Desktop using a cd without connecting to the internet at your home, you'll be able to open the file also.
I have other articles that you can rely on about QB2021. It includes installing, upgrading your company file, and support information if you need a hand with the process:
Please let me know if you have other questions about installation and upgrading QuickBooks Desktop. I'd be happy to help. Have a safe day, btks!
