Are higher end preamps worth the investment when you are only streaming Tidal & Spotify ?

Never buy equipment based on playing vinyl. Buy components that can actually handle hi-res digital audio and make it sound proper, and that is why you need a good pre-amp and other components. Your DAC and pre-amp are critical. They may be the same unit. 

“The Modwright pre 36.5 pre is definitely a pre I am looking at.”
@puffbojie

Found couple of listings for 36.5,

https://www.hifishark.com/search?q=modwright+36.5

@blisshifi

I know the info of my room is limited etc, but at first glance why do think harmonics would be a better fit vs resolution as it relates to the ARC LS28 and the ref 5 /s per my current set up?

Hello puffbojie!  If you are just streaming you don't even need a preamp. Most sttreamers with a volume control put out enough juice to drive a power amp. Save $$ and potential problems down the line. Streamer to power amp to speakers. My third best system is just DAC to power amp to speakers. Happy Listening!

I don’t see anywhere where you list the room dimensions and/or characteristics that requires Dirac to make it sound good — am I missing something?  There are lots more options than your NAD, and between its mediocre preamp and streaming capabilities you’re probably paying a very high price in performance just for Dirac.  With a budget of $10-$12k and considering the quality of your other equipment you could certainly do much better.  What’s up with the room???