I have a 1.5TB with some volumes on it. The 2 two large ones are adjacent to each other.
The first of these had about 600 GB free space and the second less than 1.5GB and that was filling rapidly. So I decided to shrink the first volume and then add the free space from that volume to the second volume. I've done this sort of thing before (on smaller HDDs) and it has always worked Ok.