Check your hard drive!
Most of the Win 10 upgrades I've seen failures on, the customer upgraded on a "going bad" hard drive.
1st thing I check and a lot of times, it's the issue.
Lots of failing drives that the upgrade seems to "brick".
New drive
Clean install
Recover what you can from old drive, professional it it's beyond your capabilities and is feasible.
oops, sorry, just saw the post about you checking the drive. Didn't see anything about it in the opening post.