I *hate* not being able to demo speakers - although in my case it’s also because all the brick and mortar stores are long gone. At least the ones with proper demo rooms. The nearest proper showroom is a 3 hour round trip and $50 parking (after validation!).
I’m familiar with the Dali Opticon and heard the Rubicon 6 briefly some time back. My demo of the Opticons was next to Dynaudio (at the far away showroom) and they were comparable, very similar voicing.
They’re punchy, fast and dynamic, if a bit more dialed back than Dynaudio IMHO.
The only potential issue I’m seeing here IIRC is they’re not the most efficient speakers. But according to your original post, you’ll only be listening at low-moderate levels. For jazz, voice, acoustic I think you’ll be delighted. Dali are world class. You might take a look on youtube and see if there’s any comparisons or reviews. Sometimes commenters own the product and can shed some additional light.