UPDATE 3/9: KB5000802 CU Windows 10 v2004 build 19041.867 and v20H2 19042.867
The KB4562830 Enablement Package allows you to go from build 19041 (v2004) to 19042 (v20H2).
Source:...
If you already updated to 661 or 662, then you will not need to manually download and install 631 since 661 and 662 is a higher build. No need to do anything.
Source: https://support.microsoft.com/en-us/help/4594440
See also:...
UPDATE 1/12: KB4598242 CU Windows 10 v2004 build 19041.746 and v20H2 19042.746
The KB4562830 Enablement Package allows you to go from build 19041 (v2004) to 19042 (v20H2).
Source:...
UPDATE 11/19: KB4594440 CU Windows 10 v2004 build 19041.631 and v20H2 19042.631
UPDATE 11/12: Fixes the in-place upgrade (repair install) issue.
KB4586853 CU Windows 10 v2004 build 19041.661 and v20H2 19042.661