Windows 2004 is a phased release and is currently just for the Insiders.
That error code generally relates to drivers but as you've extensively searched Google, you will have seen other suggestions.
You could try it as a repair install after creating a 2004 install disk after downloading it from
https://thewincentral.com/microsoft-readying-to-launch-windows-10-2004-releases-iso-rtm-build-19041-to-wsus/A repair install doesn't affect your personal stuff or installed programs.
When you have created the disk, open Windows/File Explorer - This PC - insert the disk and double click on its drive which should start the process but first open a Command Prompt (Admin) and enter these cmds -
dism /online /cleanup-image /startcomponentcleanup
dism /online /cleanup-image /restorehealth
sfc scannow
then copy & paste these cmds to the prompt where they will auto run except perhaps for the last one where you will need to press enter.
These cmds will reset the update components.
net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver
ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 catroot2.old
net start wuauserv
net start cryptSvc
net start bits
net start msiserver
Enter exit to close the cmd window then try again.
If it still fails then try it as a repair install.