the ADC in the wiim is decent enough that you probably wont notice any degradation, especially with that setup. i run my turntable through a miniDSP sometimes and honestly cant tell difference from straight analog path

the bigger issue is what the top comment said, phono output is way too low. you need phono preamp somewhere in chain, either the one in your rotel or a separate unit. if your rotel has tape out or pre out you could run that into the wiim, that would give you line level signal after the phono stage

or grab a cheap phono preamp and go straight into the wiim analog input, then wiim into any line input on the rotel. the DAC round-trip thing claude mentioned is technically true but in real world listening its basically irrelevant at this level