Hi,
I am Sumit, an Independent Advisor and a 2-Year Windows Insider MVP here to help.
Try updating to 1909 using Media Creation tool and if it fails, share the logs.
The fastest way to get the upgrade is through Media creation tool or ISO file.
Please download Media Creation Tool from the link below and select Upgrade this PC at the first screen.
https://go.microsoft.com/fwlink/?LinkId=691209
All steps, including upgrading using ISO file and Media creation tool, are covered here:
https://www.yourwindowsguide.com/2019/05/update-windows-10-may-2019-update-manually.html
Content on the above blog is written by a Microsoft MVP so it is safe.
Meanwhile, if the update fails with MCT as well.
Let us check the Installation log to find why the update failed. Please share the logs as mentioned in this article. You should use a File sharing service like Onedrive or Media Fire to upload files and share the link in the next reply.
https://answers.microsoft.com/en-us/windows/forum/all/troubleshoot-feature-update-install-failures/eaf4ff24-64d6-4c72-824c-3ba3df716fc3
The Panther logs. Files named Setupact.log and Setuperr.log from the following path C:$Windows.~BT\Sources\Panther
The Rollback logs: These usually are created if Windows Update rolls back. Files named Setupact.log and Setuperr.log from the following path C:$Windows.~BT\Sources\Rollback
[Only if the error code is 0xC1900101-0x30018] The Device Install Log from C:/$Windows.~bt\Sources\Rollback\setupapi\setupapi.dev.log
As the log size might be large consider zipping before uploading.