How do I actually downgrade Windows 10 Pro to Home?

it doesn't say why you'd want to do it exactly

In theory you just change the license key to a Home one. Windows will then block all Pro features.

↩  Tizz I don't think you can activate Pro at all with a Home license.

↩  Spicee

Run this command in PowerShell.
Set-ItemProperty -Path "HKLM:\Software\Microsoft\Windows NT\CurrentVersion" -Name EditionID -Type String -Value Core;Set-ItemProperty -Path "HKLM:\Software\Microsoft\Windows NT\CurrentVersion" -Name ProductName -Value "Windows 10 Home";Set-ItemProperty -Path "HKLM:\Software\Microsoft\Windows NT\CurrentVersion" -Name CompositionEditionID -Value "Core"
This should (hopefully) set the registry’s CurrentVersion values to Home.

Then, perform an InPlace upgrade by running the Windows installer’s Setup.exe. Unless you don’t give a fucking shit about your data, choose to keep personal files and apps.

Once the installer has completed, reboot.

You’re good to go! If you have a previous Windows 10 Home license, it should be activated by now, courtesy of a digital license.

why would you want to do this to yourself

https://www.youtube.com/watch?v=Qn977W9HjWM