Welcome to the forum Teskey. All else being equal, I have consistently preferred the DIN output to the RCA Phono whenever I’ve done comparisons in the past. It’s the reason Naim use DINs, because they feel they perform better than RCA Phonos, particularly within a complete Naim system.
Here’s a bit more on why Naim use DINs, from the FAQ:
You can have both RCA Phono and DIN outputting together however there is a performance penalty here - better to switch to either one or the other.