The FPGA in the DS is used for many functions, e.g. decoding inputs, measuring sample rates, testing for DSD doing deemphasis, buffering, upsampling and doing a sigma delta modulation to one bit DSD. The DAC part of the DS is on another board and basically comprises a passive low pas filter.
The Perfectwave DAC Mk II, like most DACs these days use a single chip for many of the above functions and most of those chips are based on multibit sigma delta, i.e. they convert PCM to a higher rate but multibit (4, 5, 6, etc.) samples via sigma delta modulation and then use multiple lower precision DACs at random to average out the manufacturing variations in those DACs.
So the functions aren’t really directly comparable, but do have some overlap.