I'm 32 yrs old, F cup, and have sagging breast. What treatment would you recommend? (photos)

Looking at your photos, I would recommend a breast reduction to decrease the size of the breasts. A breast reduction also lifts the breast to improve the shape. Having smaller breasts also minimizes the effect of gravity and help to maintain the shape long term. This is particularly so after weight loss when the skin elasticity is not as good. All the best.

Thank you for the question and pictures. Based on your description, you may be a good candidate for breast reduction surgery. “Official” recommendations of course would necessitate in-person consultation.
Breast reduction surgery is one of the most patient pleasing operations we perform. By removing “excess” breast tissue, adipose tissue, and breast skin  this operation reduces and lifts the breasts to a higher position on the chest wall. By doing so, patients often find improvement in neck, back, and shoulder discomfort and find it easier to form their activities of daily living and exercise.
Timing of the operation will depend on the patient's life circumstances. In general, it is best to do this procedure ( like all other elective body contouring the stages,  when patients have reached their long-term stable weights.  In doing so, there is an "improvement" in the safety of the procedure and the need for further surgery ( in the event of weight gain/loss after the breast reduction procedure) is minimized.
Sometimes breast  reduction surgery is covered through health insurance. The best way to obtain insurance coverage for breast reduction surgery involves some “hoops” to jump through. The more documentation you have (for example, from your primary care doctor, physical therapist, chiropractor etc.) the better when it comes to obtaining insurance “authorization” for the procedure.
 This documentation and letter/pictures from your plastic surgeon will help you obtain authorization.

When the time is right,  seek consultation with well-trained/experienced board-certified plastic surgeons. Ask to see lots of examples of their work and communicate your goals clearly.
I hope this, and the attached link, helps.

Thanks for sharing your story and congratulations on losing the 30kgs.You would benefit from a breast lift, and if you desire to be a DD/E and have more volume in the upper pole then you also need an implant.I hope this helps and good luck.