Maybe Sumit will have some comments and I will check your log tomorrow.
Your system is installed as Legacy.. The install will be in the configuration based on the way you boot the install media.
The install needs to know it is not online so it doesn't fail because it can't get some online access, so if you are changing the situation after the install starts, it may not be best.
There is a possibility that when multiple upgrade attempts have failed, there could be certain types of system corruption. You might stand down for a week or so. If the new build is released soon, will you be moving to that build?