What I might try is:
1. Clone the HDD because.
2. Now on the Clone try to get the W10 Upgrade. How?
That so you can:
A. Hope the upgrade avoids the 99 buck OS charge.
B. https://docs.microsoft.com/en-us/windows/win32/memory/memory-limits-for-windows-releases#physical-memory-limits-windows-10 does not show a Windows 10 Basic.
C. Windows 7's time is ending. I will not open a conversation about wanting to stay on W7.