A month and a half later, I beat this legitimately. Or at least I maxed out the energy, which didn't seem to do anything but I'm counting it. By the end I just let it run and fill up because that was quicker than resetting and actually buying units or buildings.
If you ever do revisit this, obviously costs should go down and the cap on mass conversion should be lessened. It just takes too long to buy anything. But more important would be to reduce or remove the energy cost on buildings. The constant resetting to convert is already very grindy, but it's downright painful when every reset deactivates all your buildings and they take so long to switch back on again.