Here is a big question , say you have a very good dac with over clock ⏰,
Logically, if you have a "very good DAC", but you need some external "reclocking" device to make it work properly, is it a "very good DAC"?
The Denafrips clock are a proprietary inter-device clock. This is different from 10MHz external clocks.
If it is USB, then there is no connection between the USB clock and the clock used for the DAC output, so what is being "cleaned". With USB, there is definitely the potential for power supply and ground noise to get on the audio output of the DAC, but that is not a clock issue. If you started with a "very good DAC", I would hope it already addresses this issue.
What are you using for your digital source? Old CD players, where the clock was synced to the mechanism, and the error correcting could even come into play often had high jitter. If your "very good DAC" is not "very good", perhaps if you are using TOSLINK, you could be introducing jitter, but that is happening at the DAC, so how is a reclocker going to help that. If you are not using a CD player, then we can assume you are streaming, and streaming sources are already starting with very low levels of jitter. Can your "very good DAC" not use an already low jitter source and give you good audio?
A "very good DAC" could transformer isolate the SPDIF, or it could have an isolated SPDIF section, which would remove the noise issue.
Is an external 10MHz clock, which has to transmit that clock via a cable, that connects to some IC in a DAC, that has to deal with the electrical noise between the two chassis (clock and DAC) going to be, without question, better than the internal clock in a "very good DAC"?
In some systems, and with some DACS, noise isolation, power supply and grounds, can be beneficial, but that is almost always about noise directly getting into the analog output, not something that impacts the DAC circuitry and especially not in something designed right. Hence if you don't hear noise that you associate with power supply/ground loop issues, then it is unlikely you have a problem.
The act of reclocking is suspect and for USB does not have meaning. If your DAC needs the input to be "reclocked" then perhaps your DAC is not as good as you thought.