I have used the Lightening DS app on an Auralic Aries Mini, it was very good but I preferred Roon, regarding Tidal and Roon, you do not need to have Tidal if you have Roon indeed many people don’t and Roon runs just fine, as for Tidal failing... who knows, Oppo ceasing trading soon seems to have come out of the blue! There are no certainties so you just have to jump in and enjoy what is available now.
One reason for preferring Roon is I can add an Auralic product to my existing non Auralic setup without changing interface, same if I wanted to add a Meridian product, with Lightening DS I can’t.