Clocking before the DAC can make a huge difference. Not speaking on theory, but experience, which matches many other’s experience as well. Too many voice their opinions, often based on theory, or just a false or incomplete understanding of how things really work, without actual experience. I’m not an expert, but know what I hear. I already have a good DAC, but added an ISO Regen and SOtM clocking device and it made a significant improvement to the sound. (And linear power supplies to the ISO ansd SOtM which brought it up yet another level.) More weight, more body, resolution, improved timbre, more "analog" (though I dislike that term). Of course you also need a downstream system capable of revealing these improvements. Many or most DACs will benefit from these devices, incuding super high-end ones. I’ve heard a few situations where there was not consistent improvement among users, such as PS Audio and Exasound DACs and maybe a few others. Likely all DACs under $2-3000 will benefit and many more over this amount. I’m not really interested in those who say why not buy a better DAC to begin with, or "USB is flawed, why bother", or especially "expectation bias" (that’s BS). Hey it’s my money and I’m having fun. If things don’t work, I sell them, but that’s not the case for these devices.
Plenty more info on this topic on the Computer Audiophile forums where users share their actual experiences and what devices brought about (or didn’t, as some work better than others) these improvements.