During COVID, I built a series of Roon endpoints with Raspberry Pis (of various types, 3/4/5), some with screens, and some with 'hats' providing DAC service. (The NanoSound Pi case with internal I2S DAC was comparatively warm and still in use as a nearfield desktop speaker endpoint for a pair of SVS powered monitors.) With the others, I swapped out a series of Topping DACs (D10s, E70 Velvet, et al.) with steady improvement. All external options improved upon the internal DAC on my integrated NAD c368.
Recently I purchased the WiiM Ultra (well-reviewed by amirm). I tested with the internal DAC, the CoAxial into the NAD, and SPIDF to the Topping Velvet. The Ultra's internal DAC and the Velvet were very good and noticeably an improvement over the NAD internal DAC on A/B testing. With room compensation enabled, I've settled on the Ultra's internal DAC, and I believe it is a distinct improvement in separation and image through my KEF LS50 metas. For now. :-)