I thinks it's because you used GParted to shrink a partition that Windows was currently using.
I've always had issues with that; last time I tried it, it corrupted my old Windows system.
Granted that was back in the time of Windows XP, but it did cause me hassle.
Windows back then didn't like other software touching it's partition
I guess it liked it's own software so that it can keep track and move files as you're shrinking it.
It has been many years since then, and they have included built in partitioning tools even into the 'home' editions.
So this may not be an issue anymore.
I believe you should have left the 128GB you left aside, by using Window's built in partitioning tool.
Then using GParted or another portioning tool to format the 128GB into ext4, or even blank/unallocated.
(which was what seemed to be what others were advising)
Then allow Ubuntu use that free space — it would detect it.
This is a chance you've corrupted the Windows partition in someway — even if it's just the Windows boot.
I hope this is not
the case, and that fixing the drivemap
error would restore your ability to boot into Windows.
Ubuntu should have the ability to detect and mount your Windows partition, and be able to access the files.
Can you do this? Try and access your files on Windows. If you can do this, it's unlikely you've corrupted the data.