Qobuz (16/44 and higher) is far better on both DACs and is my default streaming service.
Thank you for such a detailed and informative reply, Timcat! I appreciate it. Sounds like I should do a free trial of Qobuz!
Thanks again for all the suggestions everyone. After doing more research, my current thinking is that an R2R DAC would suit me very well. Although the Denafrips Ares looks like it could be great, I usually go straight into a power amp and therefore need a volume control, so I'll be eagerly awaiting the new entry-level Holo Audio (successor to the Cyan). If that is well over budget, as I suspect it will be, I'll probably just get a Gustard X16 instead.
Matt