85W laser array driver circuit
Firstly, I'm going to assume you've got enough laser safety qualifications and protective equipment to work with 85W safely, where even transient reflections can blind bystanders instantly. That's a class 4, so you need a key switch and a safety interlock to keep humans out of the area in which the beam could be.
I don't see any advantages for the battery approach unless you somehow need this to be terrifyingly portable, so I would take the mains approach.
Power transfer can only be achieved in those parts of the cycle where the input voltage exceeds the output voltage; since the output is rather high, I don't see the advantage of the 2:1 transformer other than isolation, since the voltage on the output (both AC and DC) is also lethal. From there it's &quot;just&quot; a very high voltage buck converter with a fairly large capacitor on the output.
Safety interlocks go on the output side.