S repens is an underrated carpet. I have grown it under low medium to high light. Pretty low maintenance as well. Just trim and replant. Under high light and sufficient CO2 it tends to stay “flat” and will spread laterally on its own. The root system is extensive and rivals that of crypts.
What light setting are you using with the 24/7? I’ve used the 24/7 mode and MAX (with a timer). I like the subtle changes with the former. I have the original model and the darkness period was only 3-4 at the most.