Hello boblink;
You don't have the space available at either end of the OS partition to do anything. the only thing you can do is to shrink the OS partition, which is not what you want to do.
Looking at how you have your drives setup, if it were me, I would move "K", "L", "M", "T" & "P" off the OS drive and copy them to the 2nd drive, either using the mentioned partitioning software or Aomei Partition Assistant, which has a free edition.
Moving partitions from one drive to another would be using the "Copy partition wizard" function, then once they have been copied, you can delete the original leaving you with all that unallocated space to extend the OS partition.
Keep us posted
Don