Not sure what Redbook Rates means but I’ll assume it’s higher than 44.1 x1. As such are you suggesting that the Pontus will recognize hi res from Tidal Hifi, but NOT with Hifi+ with MQA?
'Redbook' is the term for standard CD quality sample rates, or 44.1. So yes, 'HiRes' in terms of comparing it to a WAV, FLAC, etc. file, or, 'CD quality'. Certainly much better than MP3.
Bottom line, your Denafrips can provide you 'CD Quality' playback with the Tidal standard 'HiFi' plan.