Return-to-zero shift register FIRDAC

True. But there are still minor hysteresis loops around the selected operating point?

Yes, the core is never perfectly linear, just like transformers. So some form of zero field operation is desirable.

Like zero ohm source, infinite load or Infinite impedance source and zero ohm load.

In my case I used low source impedance and relatively high load impedance. And Bias and "chonky" inductors.

See here for more on distortion and inductors...