Get Glary Utilities HERE (the free version is all you need). When you're installing, I recommend turning off all check-boxes. Once installed, feel free to go to the 1-Click Maintenance tab, select all the boxes you want (I usually select all of them except Tracks Eraser), and run an initial system check.
Once that's done, go to the Advanced Tools tab, select Optimize & Improve and then Check Disk (this is just like your usual chkdsk except I've found it works better). I prefer to schedule the disk checks to occur during the next reboot to ensure nothing is accessing the drive. You'll want to check the two boxes at the bottom ("Automatically fix file system errors" and "Scan for and attempt recovery of bad sectors").
Once the disk check has finished, try the Windows 10 update again. If it fails agin, it should give you an error code. If it does, post what it is. I've got ways to fix at least a couple of dozen of these.
Good luck! ?♂️