Upgrade to Windows 11 fails after reset with no error code just "undoing changes made to your computer".

I have tried with 23H2 and 24H2 using the Windows Update, using Update Assistant, even some command prompt methods, to get this upgrade done. Nothing works. It takes an hour or so to download and install but when restarting it gets to about 88% completed then stops and says "Undoing changes made to your computer" and rolls it all back. No error number or cod is displayed. This happens with every method and both 23H2 and 24H2 WIN 11 builds. I have spent days if not weeks worth of hours trying to get this update completed and my frustration level is quite high now. My Dell G15 5511 computer is on the approved list by model number, and it's specs are far above the minimum requirements in all respects. It has over 90 GB of disk space available. There is no reason I could find that this upgrade is not working. I have been trying for months now a couple of tries a day and have run out of different methods to try or any useful ideas on what is going wrong or what to do.