IR bottom heaters are usually not strong enough for reballing. They’re for boards that are hard to solder, because there’s a lot of copper or a heatsink for example.
The bottom heater preheats the whole board, not to soldering temperatures but enough to make soldering a lot easier.
Was it ever intended or fit for that? It’s 2.5 years old, where modern games 2.5 years ago that much less demanding than modern games today?