1. Don't fix it 2. Give AccCreate a named hero in the game 3. ???? 4. Profit.
Just kidding. I recommend for donation honestly not counting any units inside zepelin but that's really not possible so I won't say anything. But honestly, if you balance the spawn of tier 3 units (or any buildings with mass spawns in general), I think donation should be fine.
It's pretty underpowered most games anyway compared to death tower and all so mehh.