Under-eye hollows - tried fillers, RF, retinol. Should I just go for a lower blepharoplasty? (Photos)

From the front lighting view that highlights (rather than masks) the problem, it would appear that the major issue here is lack of a smooth transition between the upper cheek and lower lid regions. If this is indeed so, then the skillful use in experienced hands of a robust HA volumizing filler can be used specifically and exclusively in the area of the cheek-lid junction in order to create a natural, more youthful, smooth transition between the uppermost portion of the cheek and the lowermost portion of the lower lid. I am NOT talking about using fillers directly under the eyes.
I am not at all surprised by the lack of success with RF microneedling, since microneedling is best reserved treating superficial, skin surface texture and color irregularities. (And, as an aside, the addition of the RF to professionally performed microneedling simply adds to the expense and the potential risks for adverse reactions and little to the overall results). It is not a treatment for volume replacement. You would be wise to consult with a board certified cosmetic dermatologist filler expert. In the hands of an experienced filler injector, the treatment should take about ten minutes and give rise to immediate results and engender little to no significant downtime. Hope this helps and best of luck.

It is very likely that you have malar hipoplasia, small cheek bones. This will result in hollowness of the central cheek area in an early age. Correction with cheek implants or fat grafts should be considered. Good luck.