Help an old man out

OP — I have a few thoughts to take or leave:

I own an NAD M33.  I think it sounds pretty good.  I’ve been comparing it to my Prima Luna HP Dialogue Premium integrated, using KT150 tubes, in an office sized room.  I’d give the edge to the PL, but that’s my ears, my room, my NOLA Contender 2s, etc etc.  I will say, I continue to dislike the BlueSound environment.  On a less subjective subject, the NAD is not Roon certified, if that matters to you.  Unlike earlier released models that are grandfathered in, if the NAD M33 was sold after Sept 2020, Roon will not recognize it pending certification.  Many online dealers, perhaps in-person dealers, are pitching it as Roon ready.  It’s not.  Lastly, reading between the lines of the reviews and the buzz, the focus with the NAD seems to be its all-in-one feature profile.  Yes, it’s an accomplishment.  I just don’t see a lot of buzz about the sound.  Some.  Not a lot.  

More generally, I think $5k can get you a helluva good amp.  And if you are not philosophically offended by Class D, you might consider some of the amazingly well-priced PS Audio amps.  They’ve been well-received.  I owned the BHKs a few years ago, but I have not heard their Class D stuff.  But, on paper, worth a look.    
Impedance is emphatically not a crock.  Dan D’Agostino would not say that.  Nelson Pass would not say that.  Bascom King would not say that.  Call Nelson and just ask him.  Nominal impedance specs (e.g., "this is a 4 ohm speaker," or "this one’s an 8 ohm speaker") may be unhelpful, or perhaps even "a crock."  Nomical impedance is sorta just average impedance.  But impedance dips are incredibly important, and have little to do with wattage, and little to do with sensitivity.  If a speaker has an impedance dip down to, say, 2.0 or 2.2 ohms at, say, 85 Hz, that speaker is going to be asking for a decent amount of current (not wattage) at 85 Hz.  And a little amp won’t have what the speaker is asking for.  In a way that impacts sound quality, not just volume (which is arguably all that sensitivity numbers tell you; a test tone of 1000 Hz, delivered with one watt, measured from one meter, gives you X volume, in your case 88 dB — although, I suppose if you love listening to 1 kHz tones all day, that could be enormously important).
Turning to the practical: a speaker with sensitivity of 88 dB pretty much never needs 500 watts.  Betcha the NAD, at 200, provides plenty of headroom.  It was plenty of power and current with my Harbeth 30.2s, with their low sensitivity.  And if you don’t feel like really geeking out on impedance dips, etc, I’d vote for you to keep your sights on the 100 wpc and higher amps and chances are you won’t have any power/headroom issues and can instead focus on other priorities (tone, clarity, imaging, dynamics, grip, air, lack of glare).  
My two cents.  Worth about ... two cents.  

OP -- as between the PL and the M33, my impressions (all the usual caveats):  

M33 has more grip and authority, no question.  More dynamics.  Jump factor.  But sometimes I felt that the bass and lower midrange sounded artificial, as if I had improperly integrated a small, crisp sounding sub.  Or like comparing a drum machine to actual drums.

I've been on a kick recently of hyper-focusing on attack/sustain/decay.  Decay is tricky; too abbreviated sounds nice and crisp and enunciated, but artificially so.  Too much decay eliding into the next note gets sloppy and blurred.  The M33, I think, abbreviates the decay a smidge.  I think the PL gets it right.  But perhaps with some attack edges that are a smidge, well, edgy.  More on this below.

You asked about soundstaging.  To my ears, a clear win for the PL.  More dimensionality.  The way I see it is you have a few scenarios: (i) 2D in a 2D space.  Cardboard cut-out 2D.  Yuck.  (ii) 2D in a 3D space.  Cardboard cut-out players, in a 3D space, giving you some depth and width and layering.  But each player lacks realistic shape; within that 3D space each player is 2D.  That's where I put the M33.  (iii) Then you have 3D in 3D, which is where I put the PL. 

My issue with the PL is glare and bite.  Too much of both, by a smidge.  Countless times over the last 5 years, I will pop it into a system, and think "wow, better than I remember; this thing's fantastic."  After a few weeks, that smidge of glare, edge, maybe a dash of grain, starts to become noticeable.  Countless experiences like this.  

The M33, perhaps mindful of the sins of Class D's past, doesn't do this.  It sounds good.  I like it.  I still use it in my third system.  But it doesn't quite achieve realistic imaging, air, shape, and palpability.  But, to be fair, it now lives in a room, and with stablemates, that don't exactly invite those characteristics.

Last point, I have noticed over several different speakers that the PL can sound a bit boring with particular speakers.  My previous Vandersteen Treo CTs did NOT like it.  NOLA KOs loved it.  Harbeths, somewhere between love and hate.  Wilson Sabrinas sounded awfully good on the PL, even with their not-so-easy impedance dip, but that was a 3-5 day experiment.  Just from a quick google search, I'm getting a hunch that the Gallos want more than the PL will give.

To state the obvious, while a $5k amp gets you sound that's approx 8000 times better than a barebones Sonos system, and forever enjoyable, it will not give you the sound of a $30,000 amp.  Cursed hobby.  In my own case, all I can say is to avoid listening to well set-up, well-matched, uber high end systems.  Hard to recover from those experiences and stay in love with your current gear.  Anyone who says you can get 99.9% of the million dollar sound for under $10k, hasn't heard million dollar sound in a good room.  Long way of saying that I've become a hard grader, and it's something that plagues me with my own gear.  Like you, I don't have unlimited funds, and I also have a wife who knows what "spousal parity" means, because she's smarter than I am.