DAC jitter is not the major problem people make it out to be. even the lowly, uncontrolled, $2, +-20ppm frequency stability crystal oscillator has less jitter

DAC jitter is not the major problem people make it out to be. even the lowly, uncontrolled, $2, +-20ppm frequency stability crystal oscillator has less jitter than is audibly perceptible to a human, especially given that the jitter is dependent mostly on temperature variations. you are right about bit depth. a jellybean 24-bit ADC has around 8 bits of noise floor, maybe more. To improve that, you sample at an insane rate (making jitter even less of a significant factor in the final audio) and average your measurements, and you can get 2-3 more bits out of that. my overall point is that these problems you hear from people trying to sell you audio hardware are almost all not problems at all, as far as human ears and human perception are concerned.