The Venus 15th is extremely smooth. Notsure if it would change the sound but It maybe a time for a DDC if I2S will bring a little more from the combination.
Maybe a better streamer as I am using a Wiim Pro. It would be hard to give up the ease of Wiims software.
I inserted an Iris DDC before my Musician Pegasus R2R DAC mainly to take advantage of the i2S connection and the improvement was much more than I expected and on the order of a significant DAC upgrade. Maybe @vthokie83 will chime in as he also uses an Iris with his Pontus so may be an even more useful reference point. I’d advise buying a used DDC (that’s what I did) so if it doesn’t transform your DAC you can just sell it — thinking a Hermes would be a great choice.
This site is littered with experienced people who’ve upgraded from budget streamers to more accomplished models and are very happy they did, so while I’m sure the Wiim sounds very good for the $ there’s much more to be had and I’d certainly budget for an upgrade there in the future. Everything in the streaming chain matters, and matters A LOT! Just my$0.02 FWIW, and best of luck.