I wonder how you manage your gold... I blow it every time with ampying lvl70 rainbows or with leveling high level girls with lvl5 manyu and I'm still over 4M since several months. Same on DMM. I level/evolve/bloom golds a lot but I'm always between 1M and 1.5M.
And I never use gold boost or do gold maps.
Never went beyond 1 Million
been evolving and upgrading my gurls like crazy
Oddly enough, I never did equipments
I do go broke but I get back up due to massively selling equipment and gurls since I kill non event raid bosses every day