Q.Variegated Monkey Grass
My monkey grass is flat. I divided many clumps last spring and replanted them in the same location. They produced a few purple flowers and look ok other than they are thin and flat. All my neighbors’ clumps are upright and healthy. Could I have planted them too deep? Any suggestions?

The following article might help: https://www.gardeningknowhow.com/ornamental/groundcover/monkey-grass/transplant-monkey-grass.htm
More article links follow the above article.
I would leave the foliage alone until mid-March before pruning it back to 3" high. If the crowns are level with the soil line where you transplanted, your plants are probably just reestablishing their root system. (The crown is where the fan, {the green leaves} meets the top of the roots.) If the crowns are over 1/4" below the soilline, the plants may be suffocating from being planted too deeply, and you may need to raise them.
I would wait until active growth resumes in spring to decide if you've really planted too deep. Anytime you divide, the existing leaves no longer have the support of the rest of the clump, and usually flop and look kind of pitiful. New growth should stand up straight.