For what it's worth and for noticeably more oomph, I agree that adding a sub is one relatively inexpensive way to go. Auditioning some good phono preamps is another relatively inexpensive option, as well. Upgrading the speakers and/or auditioning some quality Class A/B integrated amplifiers in the 100-WATT (RMS) range with good built-in phono sections is another. All depends on the budget. I've done several hours of serious seat-time with your TT equipped with an Ortofon Blue. That is a sweet little TT! I've never done any seat-time with any of your other specific model components. So, can't comment there. However, my ears have never particularly cared for the NAD amplifiers I've heard to date or, for that matter, Class D circuitry, in general, However, that's just MY ears. The only thing that really matters is what YOU and YOUR EARS like. If you have access to a reputable high-end audio shop or shops, tell them what you're looking for, seek suggestions and schedule some auditions with equipment that is the same or as similar to yours as possible, in a sound room that is, also, as similar to yours as possible. Some shops will even let you bring in your own components. Of course, you should always bring or play music that you like and are very familiar with for auditions. Trust YOUR EARS!

I agree with Old Audiophile. First trust your ears...not entirely what you read here. But if you think you're listening experience is lacking some warmth, I would put that on a Class D amplifier and the Exact cart. I had a similar set up (same cart with class D) and it was almost too clean and crisp for my ears. Some people dig that. I've moved through many components since then and pure class A or quality A/B integrated made a world of difference...that and speakers with bigger woofers and cabs. That said, you could try and warm it up with an external tube phono stage.

In my experience, the sound architecture often has the greatest impact on sound quality.
What I often notice is that turntables give a less exact and less detailed sound than my current setup.
Also with many CD players I have noticed that their sound architecture is sometimes not well optimized.
And if you use a CD player for a few years, it often happens that the sound quality decreases further due to wear of the parts.

This is how I solved these problems:

hardware: Infinity Alpha5 HCS II & Sony STR-DB790
software: FreeBSD in bitperfect mode with real-time sound + music player daemon

Sound demo of this FreeBSD setup
https://drive.google.com/file/d/1KLsipusqUqdvRao6HMmUOQlVt4SZNxLO/view

The shot was taken with an iPhone 13 so it's just to give you an idea.
In reality it does sound much higher quality, to the point where I would say I haven't heard any other systems that are as precise and detailed.
I have already listened to many B&W, Klipsch and Bang & Olufsen setups, but they sounded less correct (more distortion and or different timbre of the sound).

I seem to have found that FreeBSD + bitperfect mode + real-time sound is the best sound architecture currently in existence.

I would say that you already have a competent setup! Of course the speakers and the amp can always be upgraded, albeit with somewhat diminishing return... The best way is to get a lightly used REL sub, and then spend as much time as possible auditioning amps and speakers. With a good sub you might discover a reason to postpone your upgrade plans.

What I have learned is never judge a system by the brand names, the expense, the specifications, the measurements, photos of the system or what owners say about how the system sounds. The only reliable way to judge the sound is with your ears.

It would help to know what your room dimensions are, where in the room your speakers are located and where your listening position is. Also, what sort of music do you listen to? Your favorite 3-4 albums for example.

Not sure if you made any adjustments. On paper, you have a solid setup.

My only input is “what is your goal”? Is it casual listening? The feeling of the artist in the room? Having a rig that is super engaging/articulate that helps relax and clear your head (this is my personal favorite)? Or is it large scale and slam that has you hearing and feeling the music?