I've looked at some calculations, if we assume the 10A is spread out across all vias and traces, 0.3mm will handle 1/2 an amp safely, most of the pads have 2 traces supplying Vint. I have no idea how well Vint is spread out internally in the die.

To increase tolerances, we can goto a slightly thicker top layer, the only real way to test if we can continue to use 35um is probably to manufacture one test piece.