KB4474419 will not install

Any Win OS has system reserved partition, your C: drive is not the same. 

You would need to assign a letter to it first, because it is hidden by default in any Windows OS. You should be able to use windows mmc console with disk management tool to do this. Once letter is assigned you will see just as another drive:

Wrong. Only the default installation partitioning creates a system reserved partition. I know what I am saying. I created my disk partition table explicitly before installing Windows, and in that case, Windows does not create a system reserved partition. Instead, the boot files are written in the Windows partition "C:". All my partition tools (fdisk, gparted, Windows Disk Management, etc.) confirm my information.

Furthermore, assigning/removing a drive letter is pretty simple using the Windows Disk Management MMC view, except when you don't have a system reserved partition in the first place.

Any Win OS has system reserved partition, your C: drive is not the same. 

You would need to assign a letter to it first, because it is hidden by default in any Windows OS. You should be able to use windows mmc console with disk management tool to do this. Once letter is assigned you will see just as another drive:

My system does not have a system reserved partition, so I executed "fsutil usn deletejournal /N /D C:" on my Windows partition, then I tried to perform the update using the .msu archive, but it still failed.

you would need to assign a letter to it first, because it is hidden by default in any Windows OS. You should be able to use windows mmc console with disk management tool to do this. Once letter is assigned you will see just as another drive:

Also running this should clear some space

https://answers.microsoft.com/en-us/windows/forum/windows_7-performance/system-partition-nearly-full-how-can-i-find-out/d344e28c-8471-4ae4-99c1-cbf6ff55386b

In my case I needed to get into system volume information folder and get rid of log files

Okay, so how do I check the size of the system reserved partition and increase it if need be ?