Unable to install Windows 10 v1803 x64 (KB4507435)

Attempting to update Windows 10 with 2019-07 Cumulative Update for Windows 10 Version 1803 for x64-based Systems (KB4507435) has consistently failed for a couple of months now, and each time the process is the same:

• Starts the update process, gets to 30%
• Restarts
• Continues right up to 100%, then immediately gives up stating "we couldn't complete the updates / undoing changes"

Checking the event log shows (at least for the last attempt) "failed to be changed to the installed state (error 0x800f0922)".

I've tried multiple proposed fixes, none of which has had any effect:

• Ran the following from an admin PowerShell window:

dism /online /cleanup-image /restorehealth (ran to 100%)
sfc /scannow (found some corrupted files, but fixed these)
wuauclt /detectnow (didn't appear to do anything)

• Ran SC config trustedinstaller start=auto
• Deleted contents of C:\Windows\SoftwareDistribution
• Checked update history to see if the last update could be removed / reinstalled, but the entire history is blank

Current build is Windows 10 Pro v1803 (OS build 17134.523).

Any suggested workarounds for the above would be much appreciated!