I have an AI Prime reef light on a 15 gallon tank, set at 85% (12" depth) for mostly mushrooms and zoa's, you have a non-reef Prime and the settings are very low IMO.
Your flow seems ok but I have sicce nano's and they don't put out a strong flow at all. Detritus is building up on the macro algae, its easy to see in the picture, to me thats a clear indication of not enough flow IMO. I have the same macro as your pic 2, mine is under high lighting and high flow and grows like crazy,
My favia in my main tank is directly under a metal halide, IME favia's do well medium-ish light.
I politely suggest that you may be underestimating how much light and flow corals need.