What treatment would be best for my deep forehead acne scars? (Photo)

From the photo the acne scars appear to be largely rolling scars. Since most of the forehead is involved, a Field Subcision to elevate and smooth forehead would be a logical first step, followed by individual subcisions for any remaining scars that are felt to require additional lifting and smoothing. Since the forehead is so mobile, it would be wise to additionally consider the use of Botox to quiet the muscular movement of the forehead to allow for more optimal healing following the aforementioned treatments.
Following this, professionally performed microneedling (no need for the added expense and risks of RF microneedling) may be considered to treat any residual superficial, surface texture and/or color irregularities.
You would be wise to consult with a board certified cosmetic dermatologist scar treatment specialist.
Hope this helps and best of luck.