Windows 10: Windows 10 version 20H2 won't update error code 0x800f0900

Windows 10 version 20H2 alongside of other smaller updates all fail with error code 0x800f0900. I have gone through every fix I've been able to find and they all haven't worked. I've been in a live chat with a Microsoft Support person and even their recommended fix failed. I'm unable to play certain games because my Windows is outdated and I've spent so much time now trying to fix it. Any ideas?

:)

 

Windows 10 Version 1703 fails to download update KB4020821 with error code 0x800f0900

In my settings app on Windows 10 version 1703 windows update trys to to download the security update foe Adobe Flash Player ( KB4020821)for windows 10 version 1703 but fails and has an error code 0x800f0900.What can I do to get it to download and install
it.

 

Install errors - 0x800f0900

Cindy, I have tried the troubleshooting steps listed by David M. here as this person had a similar issue to me. Windows 11 Update (KB5012592) fails With Error Code 0x800f0900 - Microsoft Community I have tried all of them, I did find corrupted files and I ran windows update troubleshooter. All with no luck.

 

Feature Update to Windows 10, Version 1803 - Error 0x800f0900

OK.
I have been informed by a reliable source that the reason I cannot update to 1803 is because I have no System Reserved Partition. See image below.

What's the best method for me to create one? Also, I have read a number of articles that suggest to make it at least 500 MB, instead of the standard 100 MB.