I don't see why there could't be stabilizing adaptations for phosphate groups, or evolution of alternatives like phosphonates, thiophosphate or imidophosphate.

I don't see why there could't be stabilizing adaptations for phosphate groups, or evolution of alternatives like phosphonates, thiophosphate or imidophosphate. Evolving stable enzymes that still have catalytic activity is also a big lift, but life consistently surprises us.