A few thoughts.
First, how old is your aquarium? Parameters look good however, zoas will always do better in mature systems. You have torches so guessing it’s not recently cycled.
Secondly, zoas like nutrition, people have long misconstrued that to mean ‘they like dirty water.’ However, nutrients are an indirect measurement of the amount of nutrition in and it doesn’t account of the efficiency of your nutrient export. For example, you can be putting in a cup of food a day and skimming super aggressively, or 2 cubes a week with light skimmer and still land within the same parameters.
I feed heavily with reef roids, brine, mysis, phyto. I also clean the skimmer every other day.
Finally, not all zoas are created equal and different strains have varying tolerances for light and water parameters. Upon fragging most zoas will enter a ‘stall,’ which you seem to be experiencing. Some varieties bounce back immediately while others need several months to really get going again. I’ve found nutrition to be the #1 catalyst to get them out of a stall and growing again. Additionally, people generally grossly overestimate the amount of par they need. Many do fine in 80-120par. My trough maxes out at 150 -