Guide: How to install Windows 10 onto storage expansion card

So digging around in the documentation for these commands, I realized that the /Index:1 argument given to dism /Apply-Image is actually specifying the version of windows to install

If you do dism /Get-ImageInfo /ImageFile:R:\RecoveryImage\install.{esd,wim}, then it lists each Windows 10 version as a given index, with indices on my end being

1 == Windows 10 Home
2 == Windows 10 Home N
3 == Windows 10 Home Single Language
4 == Windows 10 Education
5 == Windows 10 Education N
6 == Windows 10 Pro
7 == Windows 10 Pro N
8 == Windows 10 Pro Education
9 == Windows 10 Pro Education N
10 == Windows 10 Pro for Workstations
11 == Windows 10 Pro N for Workstations

So if you want a version of Windows other than Home, check the indices in your image with dism /Get-ImageInfo and change the value accordingly

Looking at the other place where this index 1 shows up, I believe if a change is made with /Apply-Image then the same change needs to be made with specifying the recovery image via reagentc

Looking at

reagentc /setosimage /?

(or equivalently at the microsoft docs), we see that the index here is similarly specifying Index of the recovery image Windows imaging (WIM) file to be used by system reset

So from the sound of it, if you were to install Windows 10 Pro with /Apply-Image above and then leave this as /index 1, if you were to eventually restore your OS via the recovery partition you would have your install changed to Windows 10 Home