3.3V DAC output to 50V amplification
OK, so you basically need an audio amplifier circuit but without the high-power stage.  So here's a op-amp + Sziklai output stage amplifier that should supply 50V swing at low currents.



It simulated OK in my head, but I tried it in LTspice to get the supply current and transient response, and tune the feedback for stability.



Blue trace is 3V supply current, and red is 50V supply current.  The other two are input and output.

You could save some quiescent current by using a 1.5 V supply for the emitter voltage instead of the 40k+40k divider.  20k to a normal rail-splitter circuit would work.