@old_ears
Whatever the digital connection, synchronous or asynchronous, both the source’s clock and the DAC’s clock will both be in play. There will be a handshake between the two of them. It’s just a matter of which clock will be the controlling or “boss” clock for the interaction.
With synchronous connection, such as via I2S, AES, or Digital Coax, the source clock will be the boss clock.
With asynchronous connection via USB, the DAC clock will be boss.
But either way, both clocks will be in play.