@fritzenheimer I don't have your NAD, nor do I have any experience with the Rega phono. That said, according to AI it describes the sound of the two as follows:
"The Rega Fono MM MK5 is a dedicated external phono stage known for a dynamic, punchy, and musical sound with excellent detail and a wide soundstage
. In contrast, the NAD M33 has a very capable built-in phono stage, but its sonic signature is more restrained, often described as warmer, cleaner, and slightly veiled compared to the Fono MM's detail and excitement. For a vinyl enthusiast seeking the most engaging and detailed vinyl playback, the Rega Fono MM MK5 is likely the superior choice, while the NAD M33's built-in stage provides a more balanced and laid-back sound that some may prefer.
Does the descriptive of the NAD match that of your listening experience with it? If so, do you like that presentation ,or would you prefer the sound as AI describes for the Rega? If unsure, maybe consider calling say Upscale Audio and discuss with them as they carry both Rega and NAD; and potentially if there's a different/better recommendation for your sound preference within your budget.