Would Botox work to minimize? Is filler a better option?
I would recommend a neuromodulator like Botox or Dysport to relax the glabellar muscles to begin with. Regular treatments should reduce the size of these muscles. If there is any forehead volume loss, it could be treated with an HA filler.
In the pictures it appears that you have very strong corrugator muscles. I would start treatment with neurotoxin (Botox/Dysport/Xeomin) and see what degree of improvement you obtain once the muscles atrophy or shrink. If this does not bring adequate improvement I would suggest you consult an experienced facial surgeon who can discuss surgical options. I would not recommend trying to fill the "crater" with filler. Best regards, Dr. Tkatch