Install MiniTool Partition Wizard. I have used this.
https://www.partitionwizard.com
Should be easy to merge the unallocated partition to where you want. The other question about TRIM I cannot answer.
Googled: will “TRIM” etc. spread the wear out over the entire drive, including the unallocated partition
https://tinyurl.com/2p9pdjew
What is trim and active garbage collection?
https://www.crucial.com/articles/about-ssd/what-is-trim
(Scroll down to answer from "Jon" of Micron)
ANY UNUSED SPACE is used to manage garbage collection and wear leveling. It doesn't matter if it's unpartitioned space or if is it is simply unused within the partition.
(typo correction mine)
So, for all intents and purposes, I can leave it alone, and, if I ever use up the 222 GB of "C:", I can create another drive in the unallocated space to move a few apps (programs) into, esp. if such would do many writes to the folder or drive it is in.
For all practical purposes, this drive should easily outlive me. Maybe my daughter, too. Although, that begs another question:
Does reading data on a SSD or USB flash drive "refresh" it?