Critique my system...

If you are presently using the amplifier's 8 ohm tap, corresponding to the rated nominal impedance of the speaker, try the 4 ohm tap.

I have no particular familiarity with the Boxer, and I couldn't readily find any info on how its impedance varies as a function of frequency. But many small two-way speakers have a considerably lower impedance in the bass region than at higher frequencies, the expectation being that the interaction of that kind of impedance characteristic with the near zero output impedance of most solid state amplifiers will result, for a given signal level, in increased power delivery at low frequencies, relative to power delivery at high frequencies. Thereby compensating to some extent for the limited bass capability that a small two-way will tend to have.

That increase in low frequency power delivery will not occur to the same degree with a tube amplifier, due to its relatively high output impedance. But the output impedance of the 4 ohm tap will be significantly less than for the 8 ohm tap.

If that doesn't help sufficiently, room acoustics, speaker placement, and the direction in which the speakers are aimed would probably be what I would focus on next. For one thing, if they are presently aimed at the listening position try aiming them straight ahead.

Regards,
-- Al

If what Al said doesn't resolve it, experiment with speaker placement and toe-in/out so that less sound reaches your ears directly from the tweeters and see if that helps.

Grills on or off the Boxers? That may make a difference if off currently.

Or try placing a piece of light felt or similar acoustically translucent material over the tweeters just for fun and see what that does. If it helps, leave it there. Tweak the amount of material used to obstruct the tweeter until you get the desired results with grilles on for best WAF.

All easy low/no cost things to try before changing anything. You'll probably learn more about how the gear performs along the way as well which can only help prior to making a change if it comes to that.

Brightness aside, how does the bass sound? Moving speakers around to different locations should have an effect there as well which might help with tonality overall. Those Nola's are rear ported, right? That would suggest they may do best overall including with the bass a couple feet or more out and away from front wall. Some distance from side walls as well to help avoid early reflections that smear the sound that might be heard otherwise is probably desirable as well.

Trying different ICs, not necessarily real expensive ones, might be the next thing I would fiddle with. A used pair of MIT Terminator 3 or 4 ICs for well under $100 might have a softening effect on the tonality overall.

Oh, and of course, whenever tubes are involved, make sure they are strong and functioning up to spec or else all bets are off.

It looks like a good system. I agree re the Monster ICs etc. get something else. The CDP could be "better" but with your amps and speakers you shouldn't lack warmth, there is no desperate need for more tubes. I think you can go overboard with warmth, so some balance isn't bad. Again for a first serious system you did a good job, I wish I had done as well.

I would first look at room acoustics and speaker placement

If its a hard and cold room, throwing money at the equipment wnd isn't going to get you to your goal

The most important cables are the power cords.