Best way to treat permanent vertical indentation between the eyebrows? (Phtoo)

I have an indentation between my eyebrows. I have Botox to stop the frown but the indentation is still noticeable when light shines across my face. My cosmetic doctor advised against filler in this area as it is too dangerous. She recommended Sunekos (3 treatments) to add volume to my forehead stating that this would help fill the indentation. Sunekos made no difference. Please could you advise if fillers are an option and in this case which ones or if you would recommend another treatment.