Yvette222

I have seen problems similar to yours caused by the firmware, check if you have firmware updates available for both your SSD and your HDD.

I tried the same thing using MiniTool Partition wizard. Both Copy Disk and Migrate os function can copy OS.

Personally, it's difficult to merge the unallocated space using Windows Disk Management. But you can try a third party partition tool, such as minitool partition tool, easeus partition master, etc. Normally, the Free versions would fix your issue. For example, in MiniTool Partition tool, you can right click partition G, and the Move/Resize feature can help you change the location between this partition and the unallocated space. 
 

How about Diskpart clean? 

Hello, i just said what i thought. If easeus free tool can convert the disk from dynamic to basic, then it's better. As far as i know, many partition tools can convert dynamic disks, but many of them (including easeus partition tool) need the paid version. For your reference: https://www.easeus.com/partition-manager/epm-free.html

Have you tried making a virus scan on this drive? 
You can also clean it using Diskpart or format it in minitool partition program, and see whether you can reuse this drive. If neither can help you, probably it's already dead.

I think probably there are bad sectors on your drive, you'd better back up important data.
By the way, you can use CrystalDiskInfo to test it's current status, you can also use minitool partition software to test whether it has bad sectors.
 

You need to root your phone in advance. In this post, here are detailed steps to add phone storage space with SD card, maybe you can have a look: https://www.partitionwizard.com/increase-internal-storage-android/use-memory-card.html