Maxed everything out. Still couldn't fix the "smart investment". Probably only works with smaller numbers or something. Been clicking on "complete roll" to het the phantom cube boost for 15 minutes. Reached EH 6D
I think D7 EH legitimately is only theoretically possible, but not in this universes's timeline.
Its a fun timewaster, but not satisfying at all. Most likely the probles is that production isn't scaling or increasing automatically after all the upgrades. And smart investment not working.