This will be a long post, regrets.
I am using my Western Digital My Book for the example, it housed 48 partitions, numbered sequentially, except for /dev/sdb2
*
SCREENSHOT 1 - About to delete /dev/sdc19
I've checked the content of /dev/sdc19 and I don't need it so for now I will delete it, and create a new partition elsewhere.
SCREENSHOT 2 - Deletion done
With KDE Partition Manager, as with GParted, at the bottom of your open window, you get Pending Operations listed, when you are ready, with KDE you go to top left and click the Apply button.
SCREENSHOT 3 - Creating new partition
I have decided not to replace the deleted partition on the spot and in the same place. If I did so, it would become a new /dev/sdc19.
Instead I have gone to near the end of my drive, and am creating a 10 GiB partition labelled 4Linux-dot-org.
SCREENSHOT 4 - Changes Applied, new partition created and numbered automatically
Here, I have chosen to Apply all changes, and the result below /dev/sdc48, shows the new partition has been created. Because I did nothing to replace the earlier /dev/sdc19 that I deleted, Linux has allocated /dev/sdc19 to the partition labelled 4Linux-dot-org.
This now resembles, a little, what the OP has in #3. Numbers are out of order.
You can also note that
* I keep my /boot/efi's at the
end of my drives, , here /dev/sdc2, makes for easy resizing by redeeming some space from Unallocated Space above it.
But wait! I then decide that my /dev/sdc48 Photorec partition does not need 20 GiB, I will give 10 GiB of that to the new partition.
SCREENSHOT 5 - /dev/sdc48 shrunk, /dev/sdc19 expanded
I have resized /dev/sdc48 down by 10 GiB (temporarily results in 10 GiB Unallocated Spaced), followed by resizing the new /dev/sdc19 up by 10 GiB. I have then Applied all changes, and the above is the result.
Note that while the numbering varies (/dev/sdc48 to /dev/sdc19) that does not matter, as the partitions are
aligned by each other.
HTH
Wizard